C-553/24

Provisional text OPINION OF ADVOCATE GENERAL ĆAPETA delivered on 4 June 2026 (1) Case C‑553/24 Assemblée nationale de la République française v European Parliament Council of the European Union ( Area of freedom, security and justice – Common asylum and immigration policy – Regulation (EU) 2024/1351 – Asylum and migration management – Solidarity mechanism – Principle of subsidiarity – First paragraph of Article 8 of Protocol (No 2) on the application of the principles of subsidiarity and proportionality – Action notified by a Member State on behalf of its national parliament – Jurisdiction of the Court of Justice – Admissibility – Distinction – Principle of conferral – Principle of proportionality – Procedural and substantive subsidiarity – Intensity of judicial review ) I.      Introduction 1.        In the present case, a minority of members of the Assemblée nationale de la République française (the National Assembly of the French Republic; ‘the National Assembly’), one of the chambers of the French Parliament, (2) has brought an action before the Court of Justice on the basis of Article 8 of Protocol (No 2) on the application of the principles of subsidiarity and proportionality. (3) 2.        They seek the annulment of Regulation (EU) 2024/1351 on asylum and migration management. (4) 3.        This is the first time, since its introduction by the Lisbon Treaty, that Article 8 of Protocol No 2 has been used by a national parliament. 4.        An action challenging the legality of an EU legislative act on the basis of that provision is confined to a breach of the principle of subsidiarity as a possible ground for annulment. This case therefore invites the Court to distinguish the principle of subsidiarity from other principles in the Treaties related to the division of competences between the European Union and the Member States, namely the principles of conferral and proportionality. II.    Procedure before the Court 5.        By its application lodged on 14 August 2024, the National Assembly brought the present action before the Court on the basis of the first paragraph of Article 8 of Protocol No 2, in accordance with the relevant provisions of the French Constitution, (5) which allow a minority of at least 60 deputies to do so. 6.        The application was transmitted to the Court by the French Government, which emphasised that it was brought by the National Assembly alone, and not by France as a Member State. 7.        The National Assembly requests that the Court annul Regulation 2024/1351 in its entirety or, in the alternative, annul Part IV of that regulation concerning solidarity. 8.        In their defences, each lodged on 7 November 2024, the European Parliament and the Council of the European Union request the Court to dismiss the action and to order the National Assembly to pay the costs, or, in the alternative, in the event that the Court upholds the action, to maintain the effects of the annulled regulation or of the annulled provisions until the entry into force, within a reasonable period, of a new regulation or new provisions intended to replace them. 9.        The National Assembly also lodged a reply on 18 December 2024, and the Parliament and the Council each lodged a rejoinder on 30 January 2025. 10.      By decision of 17 December 2024, the President of the Court granted leave to Hungary to intervene in support of the form of order sought by the National Assembly. 11.      By decisions of 19 November and of 12 and 17 December 2024, the President of the Court granted leave to the Hellenic Republic, the Kingdom of Spain and the European Commission to intervene in support of the form of order sought by the Parliament and the Council. 12.      The Court decided, pursuant to Article 76(2) of its Rules of Procedure, to give a ruling without a hearing. III. The challenged act: Regulation 2024/1351 13.      Regulation 2024/1351, the annulment of which is sought by the present action, (6) is part of the new EU Pact on Migration and Asylum. (7) 14.      That pact is a package of EU measures reforming the EU asylum and migration legal framework that entered into force in 2024, and which generally becomes applicable in mid-2026. (8) 15.      In a nutshell, as is clear from Article 1 thereof, Regulation 2024/1351 aims to do three main things. First, it establishes a common framework for the management of asylum and migration in the European Union, so as to ensure a comprehensive and integrated approach. (9) Second, it lays down rules to replace Regulation (EU) No 604/2013, (10) commonly referred to as the Dublin III Regulation, regarding the criteria and mechanisms for determining the Member State responsible for examining applications for international protection. (11) Third, it introduces a mandatory solidarity mechanism to support Member States in addressing situations of migratory pressure. (12) It is that solidarity mechanism which lies at the heart of this case. 16.      In that respect, recital 22 of Regulation 2024/1351 explains: ‘In order to ensure a fair sharing of responsibility, solidarity as enshrined in Article 80 TFEU and a balance of effort between Member States, a mandatory solidarity mechanism should be established which provides effective support to Member States under migratory pressure and ensures swift access to fair and efficient procedures for granting international protection.’ According to recital 40 thereof, that mechanism is, ‘together with an effective system for determining the Member State responsible, a key prerequisite to the functioning of the Common European Asylum System as a whole’. 17.      To that end, Part IV of Regulation 2024/1351, entitled ‘Solidarity’, sets out detailed rules on the solidarity mechanism. Relevant for the present case, Article 56 of that regulation establishes the Annual Solidarity Pool, comprising the contributions pledged by the Member States and which serves as the main solidarity response tool for Member States under migratory pressure. (13) According to Article 56(2) thereof, that pool consists of the following types of solidarity measures, to be provided by the Member States: (a) relocations (14) of applicants for international protection; (b) financial contributions; and (c) alternative solidarity measures, such as operational support, staff support, facilities and equipment. In pledging their contributions, Member States have full discretion in choosing between those types of solidarity measures or a combination thereof.(15) 18.      As far as relocations are concerned, Article 67 of Regulation 2024/1351 delineates the procedure before relocation. In particular, it specifies that the benefitting Member State must, before applying that procedure, ensure that there are no reasonable grounds to consider that the person concerned poses a threat to internal security and is to transmit to the Member State of relocation all relevant information; that latter State can then check whether there are such grounds and confirm whether relocation can take place, which must be done within one week of receipt of the relevant information from the benefitting Member State or within two weeks in complex cases. (16) 19.      Article 68 of Regulation 2024/1351 details the procedure after relocation. It indicates, inter alia, that where an applicant has been relocated, responsibility for examining the application for international protection is transferred to the Member State of relocation. (17) 20.      Additionally, Article 63(5) of Regulation 2024/1351 provides that a contributing Member State which has not implemented its pledges or accepted relocations equal to its pledged relocations by the end of a given year must, at the request of the benefitting Member State, take responsibility for applications for international protection for which the benefitting Member State is responsible up to the number of relocations pledged as soon as possible after the end of that year. IV.    Main arguments of the parties 21.      The National Assembly, supported by Hungary, argues that Regulation 2024/1351 infringes the principle of subsidiarity as defined and guaranteed by Articles 4 and 5 TEU. That regulation establishes, in particular in Articles 56(2), 63(5), 67 and 68 thereof, a regime for the relocation of applicants for international protection to the detriment of the sovereignty, national identity, integrity of constitutional structures and the security of the Member States, which are obliged to receive on their territory third-country nationals who are the subject of the relocation measures. 22.      The National Assembly, in essence, relies on five sets of claims. 23.      First, the National Assembly contends that Regulation 2024/1351 disregards Article 72 TFEU, (18) which incorporates the ‘national security reserve’ of competences belonging to Member States from Article 4(2) TEU into the area of freedom, security and justice. That regulation establishes a procedure for the relocation of third-country nationals who have entered the EU territory illegally with the aim of obtaining a right of residence in the territory of the Member States, which in reality is not justified by the existence of genuine persecution in their countries of origin. The relocation measures are liable to cause significant upheaval of the national identity of the contributing State and require it to expend material and human resources on such a scale as to affect its constitutional structures. 24.      Second, the National Assembly submits that the relocation regime prevents Member States from carrying out their essential State functions, and in particular the maintenance of law and order and the safeguarding of national security, those competences remaining the sole responsibility of each Member State within the meaning of Article 4(2) TEU. (19) The provisions of Article 67 of Regulation 2024/1351, making the reception of relocated persons subject to the agreement of the contributing State and the possibility afforded to that State to oppose relocation on national security grounds, are illusory, as they prevent Member States from effectively invoking national security. In reply to the Council’s objection that it did not indicate how the objectives of Regulation 2024/1351 could have been better achieved by the Member States than by the European Union, the National Assembly argues that it is the objectives themselves, in that they consist in developing a common policy on asylum and immigration, which jeopardise the essential functions of the State and are therefore contrary to the principle of subsidiarity. 25.      Third, the National Assembly asserts that Regulation 2024/1351 has harmful financial consequences. The participation of Member States in the relocation regime when they do not wish to accommodate applicants on their territory is calculated on the basis of total GDP and population size, and thus does not take into account the reception capacity, social policy, identity and security situation of the Member State. Nor are the financial consequences of a subsequent refusal to relocate set out in that regulation, with the result that it is possible for the Commission to implement financial arrangements penalising Member States that have acted to safeguard their national interests. Therefore, the relocation regime undermines the obligation of social policy as referred to in Article 151 TFEU, since it risks creating unreasonable burdens on the contributing State regarding its social expenses, and even if that regulation leaves discretion to the Member States as to the type of solidarity measure chosen, the fact remains that, whatever the choice made, it is a burden on the State. 26.      Fourth, the National Assembly complains that Regulation 2024/1351 was adopted without any demonstration of its usefulness in relation the relocation regime. 27.      Fifth and finally, the National Assembly submits that there is nothing to indicate that the Member States would not have been able, either alone or in cooperation, and more effectively than the European Union, to manage the problems caused by the mass influx of applicants for international protection. 28.      The National Assembly concludes that the relocation regime, which is not provided for in Title V of the FEU Treaty, exceeds the competences of the EU institutions and disregards the principle of subsidiarity. 29.      Hungary adds that the EU legislature bears the burden of demonstrating whether it is at the national or EU level that the implementation of a task or measure is the most effective, including the burden of demonstrating that the performance of a given task by a given Member State is not sufficiently effective. 30.      The Parliament and the Council, supported by Greece, Spain and the Commission, challenge the admissibility of most of the claims put forward by the National Assembly. They submit that an action brought under Article 8 of Protocol No 2 can only relate to the principle of subsidiarity. In their view, claims relating to alleged infringement of Article 4(2) TEU, Article 72 TFEU and Article 151 TFEU, along with the alleged harmful financial consequences and the failure to demonstrate the usefulness of the relocation regime, do not concern that principle. 31.      The Council emphasises that the achievement of the objectives of Regulation 2024/1351, which consist in developing a common policy on asylum and immigration, is provided for by primary EU law and cannot in itself constitute a breach of the principle of subsidiarity. The Parliament asserts that the assessment of how best to achieve the objectives of the envisaged action is not for the Member States, but for the European Union to carry out. The Commission adds that the principle of subsidiarity does not call into question the competence of the EU legislature to act under a concrete legal basis, nor the objectives that the EU legislature has set for itself for such action, but only the decision to achieve those objectives by the contested act. 32.      As a matter of substance, the Parliament and the Council, supported by Greece, Spain and the Commission, submit that Regulation 2024/1351 complies with the principle of subsidiarity. The EU legislature correctly considered that the objectives relating to solidarity pursued by that regulation could be better achieved at the EU level, and the National Assembly’s arguments that it has not been demonstrated that they could not be sufficiently achieved by the Member States cannot be accepted. 33.      They stress that the National Assembly has not put forward any concrete arguments to demonstrate that the objectives of that regulation could have been better achieved by the Member States than by the European Union. 34.      The Parliament adds that both the substantive conditions and procedural guarantees related to subsidiarity have been respected, as the objectives pursued by that regulation have a cross-border dimension and can be achieved only at the EU level, and there is a sufficient statement of reasons showing the advantages of EU action. The Council asserts that it would be extremely difficult, if not impossible, to devise an adequate system of solidarity by relying solely on actions of the Member States. 35.      For Greece, the tools available to each Member State alone are not sufficient to manage the phenomenon of mass migration across the European Union, and previous EU legislation did not provide for tools to deal with situations of migratory pressure faced by Member States. For Spain, Regulation 2024/1351 is an application of the principle of subsidiarity par excellence, in terms of the need to address at the EU level objectives that cannot be achieved individually by the Member States, especially with regard to solidarity. 36.      The Commission underlines that the fact that Member States may cooperate in a way other than under instruments of EU law is irrelevant, and that that regulation reproduces numerous elements of the Commission’s proposal, which made it clear that action taken at the level of individual Member States was insufficient and that action at the EU level was required. V.      Analysis 37.      As mentioned in the Introduction, the present case is the first action brought by a national parliament on the basis of Article 8 of Protocol No 2. 38.      The possibility given to national parliaments to initiate judicial review on grounds of an alleged breach of the principle of subsidiarity is part of broader efforts introduced by the Lisbon Treaty to enhance the effectiveness of that principle as a limit on the exercise of legislative powers at the EU level. (20) In that respect, national parliaments acquired the right to be informed about EU legislative proposals, (21) and have been empowered to submit a reasoned opinion if they consider that such a proposal is not in conformity with the principle of subsidiarity, (22) in a procedure that is often referred to as the early warning mechanism. 39.      Whereas such political control of subsidiarity by national parliaments is possible ex ante, that is, before the adoption of a legislative act, judicial control on the basis of Article 8 of Protocol No 2 can be initiated ex post, after the adoption of such an act. Those two procedures are not mutually dependent, in the sense that a national parliament may introduce an action under Article 8 of Protocol No 2 even if it did not submit a reasoned opinion in the context of the early warning mechanism. (23) Therefore, even if the National Assembly did not submit a reasoned opinion regarding the proposal for Regulation 2024/1351, (24) this does not prevent it from challenging that act before the Court. 40.      However, an action provided for by Article 8 of Protocol No 2 can be brought, on the basis of the text of that very provision, only ‘on grounds of infringement of the principle of subsidiarity by a legislative act’. As seen above (point 30 of the present Opinion), the Parliament and the Council, supported by Greece, Spain and the Commission, contend that the majority of the National Assembly’s claims do not concern that principle. Before engaging with those claims on the merits, the Court should therefore decide which of those claims are admissible. For that purpose, it is necessary to make a distinction between the claims that concern the principle of subsidiarity and those that pertain to other principles which concern the existence and exercise of EU competence, namely the principles of conferral and proportionality, respectively. 41.      Taking the foregoing into account, my analysis is structured as follows. Given its novelty, I will first examine the question whether the Court has jurisdiction to rule on the present action (A). I will then turn to the question of admissibility of the claims put forward by the National Assembly, which requires the Court to determine how the principle of subsidiarity should be distinguished from the principles of conferral and proportionality (B). Lastly, I will assess the merits of the admissible claims put forward by the National Assembly (C). A.      Jurisdiction 42.      It should be noted at the outset that the issue of the Court’s jurisdiction to rule on an action brought on the basis of the first paragraph of Article 8 of Protocol No 2 has not been disputed in the present case. 43.      Nonetheless, it is settled case-law that the question of the Court’s jurisdiction over an action is a matter of public policy, which may be considered by the Court at any stage in the proceedings, even of its own motion. (25) 44.      In the present case, seeing as it is the first time that the Court is called upon to rule on this type of action, I consider it necessary to address that issue. 45.      According to the first paragraph of Article 8 of Protocol No 2: ‘The Court of Justice of the European Union shall have jurisdiction in actions on grounds of infringement of the principle of subsidiarity by a legislative act, brought in accordance with the rules laid down in Article 263 of the Treaty on the Functioning of the European Union by Member States, or notified by them in accordance with their legal order on behalf of their national Parliament or a chamber thereof.’ (26) 46.      That wording refers to the ‘Court of Justice of the European Union’, thus encompassing the Court as an institution, including the Court of Justice and the General Court. It might therefore be wondered whether the General Court has jurisdiction to rule on this action at first instance. 47.      In my view, there are a number of reasons that militate in favour of finding that it is the Court of Justice, and not the General Court, which has jurisdiction to rule on an action brought by a national parliament on the basis of Article 8 of Protocol No 2. 48.      First, the method by which the Treaties bestow jurisdiction on both EU Courts is by referring to the Court of Justice of the European Union as an institution. (27) The actions which can be heard by the General Court at first instance are then expressly enumerated in Article 256 TFEU (28) or specified in the Statute of the Court of Justice of the European Union (‘the Statute’). (29) 49.      The reference to the Court of Justice of the European Union in Article 8 of Protocol No 2 is thus the usual method which is used in the Treaties to bestow jurisdiction on the EU Courts. In order to grant jurisdiction to the General Court, an express provision would be necessary in the Treaties or the Statute. However, no such provision granting jurisdiction at first instance to the General Court to hear actions under Article 8 of Protocol No 2 exists. 50.      Second, it could be considered that the action based on that provision is simply a version of the action for annulment, regulated in Article 263 TFEU, over which Article 256(1) TFEU grants, in principle, jurisdiction to the General Court unless the Statute reserves it to the Court of Justice. Article 51 of the Statute reserves to the Court of Justice, inter alia, jurisdiction in actions for annulment brought by a Member State against a legislative act. 51.      It follows from the wording of Article 8 of Protocol No 2 that the action may be brought by a national parliament as distinct from the Member State (‘brought … by Member States, or notified by them in accordance with their legal order on behalf of their national Parliament or a chamber thereof’). A chamber of a national parliament thus decides on its own to initiate the action, whereas the government of the Member State concerned is merely to transmit such an action, as was done in the present case. 52.      Granting a Member State, as represented by its government, a right to bring the action on the basis of Article 8 of Protocol No 2 to the Court of Justice does not change the rights of the Member States, as they may already bring actions for annulment on the ground of breach of the principle of subsidiarity to the Court of Justice on the combined reading of the second paragraph of Article 263 TFEU, Article 256(1) TFEU and Article 51 of the Statute. Thus, the reason for including Member States in Article 8 of Protocol No 2 might simply be a wish to stress that the principle of subsidiarity is justiciable. However, granting the right to Member States’ parliaments is a novelty introduced by that provision. Coupling a Member State qua government with the same Member State qua parliament in the same provision suggests that the action provided for in Article 8 of Protocol No 2 should be brought before the same Court in both cases. As the Member State qua government is to bring such an action before the Court of Justice, that is an argument in favour of concluding that the national parliament must also bring the action under Article 8 of Protocol No 2 before the Court of Justice. 53.      Third, the action under Article 8 of Protocol No 2 is not the same action as the one brought on the basis of Article 263 TFEU, even though the object of both actions is the same – the annulment of an EU act. The former action is, however, a special or sui generis form of action for annulment. (30) 54.      There are several arguments in favour of considering that action as a sui generis action. 55.      In the first place, an action under Article 8 of Protocol No 2 does not depend on the conditions for standing set out by Article 263 TFEU. Thus, national parliaments do not have to satisfy any conditions to have access to the Court of Justice to challenge an EU legislative act on grounds of infringement of the principle of subsidiarity. 56.      In that respect, it is relevant that the second paragraph of Article 8 of Protocol No 2 enables the Committee of the Regions to bring an action ‘against legislative acts for the adoption of which the Treaty on the Functioning of the European Union provides that it be consulted’. Thus, that body does not have to demonstrate that it is bringing the action in order to protect its prerogatives, a condition which it would have to fulfil under the third paragraph of Article 263 TFEU. 57.      In the second place, another important difference lies in the scope of the two actions – unlike an action under Article 263 TFEU, which can be introduced on a number of grounds specified in the second paragraph thereof, an action under Article 8 of Protocol No 2 can be based only on a claim of breach of the principle of subsidiarity. 58.      In the third place, there is a difference in the type of potential applicants. Unlike the action under Article 263 TFEU, an action under Article 8 of Protocol No 2 can be brought only by the Member States, their national parliament or a chamber thereof, and the Committee of the Regions. 59.      Being a sui generis action, the action under Article 8 of Protocol No 2 could be considered to fall within ‘other cases provided for in the Treaties’ for the purposes of Article 19(3)(c) TEU. 60.      In that respect, jurisdiction granted to the General Court under Article 256(1) TFEU, read in conjunction with Article 51 of the Statute, to hear at first instance certain actions for annulment does not cover the action under Article 8 of Protocol No 2. Jurisdiction for hearing that special type of action has not been expressly granted to the General Court. 61.      Fourth and finally, I observe that Article 8 of Protocol No 2 refers to the rules of Article 263 TFEU (‘brought in accordance with the rules laid down in Article 263 [TFEU]’). However, that reference does not equate that novel action with the action for annulment in Article 263 TFEU; quite the contrary, it treats that new action as a separate one borrowing certain aspects from Article 263 TFEU. As I have already explained, that reference does not concern the potential applicants, the standing conditions or the grounds for annulment. It may thus be considered that the reference to the rules of Article 263 TFEU concerns the procedural aspects of the action, such as the time limits as well as the effects that follow if the Court were to find the annulment claim well founded. Therefore, the reference to Article 263 TFEU in no way changes the previous finding of the sui generis nature of the action under Article 8 of Protocol No 2. 62.      To conclude, in my view, and as indicated by the Parliament as well as the French Government in its transmittal letter, (31) an action brought on the basis of the first paragraph of Article 8 of Protocol No 2 establishes a specific remedy designed to enable a national parliament or one of its chambers, in view of their role in ensuring compliance with the principle of subsidiarity as set out in primary EU law, to bring an action before the Court of Justice for infringement of that principle. 63.      Therefore, I consider that the Court of Justice has jurisdiction to rule on the present action. B.      Admissibility 64.      As explained, the Parliament and the Council, supported by Greece, Spain and the Commission, contest the admissibility of the majority of the National Assembly’s claims. 1.      Action confined to claims of alleged breaches of subsidiarity 65.      In contrast to an action for annulment under Article 263 TFEU, which can be brought on a number of grounds including the principle of subsidiarity, (32) an action brought on the basis of Article 8 of Protocol No 2 is confined to allegations relating to a breach of that principle. 66.      First, this follows clearly from the wording of the first paragraph of Article 8 of Protocol No 2 (‘on grounds of infringement of the principle of subsidiarity’). 67.      Second, in terms of context, while the principles of conferral, subsidiarity and proportionality are set out side-by-side in the provisions of Article 5 TEU, (33) only the second subparagraph of Article 5(3) TEU provides that: ‘National parliaments ensure compliance with the principle of subsidiarity in accordance with the procedure set out in that Protocol.’ A comparable provision is absent in the second subparagraph of Article 5(4) TEU relating to the principle of proportionality, even though Protocol No 2 relates to both the principles of subsidiarity and proportionality. There is also no mention of national parliaments in relation to the principle of conferral as set out in Article 5(2) TEU. (34) 68.      Third, as regards the origins of Article 8 of Protocol No 2, such an interpretation seems to be supported by documents exchanged in the context of the European Convention. In relation to the early warning mechanism, it was discussed which principles relating to EU competences should be controlled by national parliaments, and proposals to include the principles of conferral and proportionality were rejected, while such control was introduced only in relation to the principle of subsidiarity. (35) Possible recourse to judicial proceedings was considered only with regard to the principle of subsidiarity. (36) Thus, it seems that the intention of involving national parliaments was to include them in the political and judicial control of the principle of subsidiarity only. 69.      To conclude, I consider that the scope of an action brought by a national parliament on the basis of Article 8 of Protocol No 2 is limited to the principle of subsidiarity. Therefore, claims put forward must concern that principle, or they are inadmissible. 70.      That said, the problem that this case raises is what is subsidiarity and, in particular, how to distinguish that principle from the principles of conferral and proportionality. In fact, the parties to these proceedings seem to agree that the present action is limited to the principle of subsidiarity. However, they disagree as to whether certain claims advanced by the National Assembly may be considered to relate to that principle. 71.      In that respect, studies demonstrate that, in the context of the early warning mechanism, which is also confined to the control of the principle of subsidiarity, national parliaments understand the meaning of that principle differently. (37) For instance, they sometimes include arguments concerning the content of a legislative proposal, such as criticising the appropriateness or necessity of the proposed measures, or question the lack of a proper legal basis for the European Union to act. This demonstrates that the dividing line between these principles, all expressed in Article 5 TEU, is fluid. 72.      Turning to the judicial review of the principle of subsidiarity, in the case-law, when claims relating to that principle have been brought on the basis of actions for annulment under Article 263 TFEU, they have usually been raised alongside claims challenging the existence of EU competence or the proportionality of the EU measure. (38) In such cases, it was not indispensable to draw a strict line between those principles, as the Court, when ruling in the context of such actions, has competence to take into consideration all three principles in order to decide on the legality of the measure. (39) 73.      However, as explained, the action which national parliaments may bring on the basis of Article 8 of Protocol No 2 is confined to the principle of subsidiarity. Therefore, in order to determine the admissibility of the claims put forward by the National Assembly, the present case invites the Court to distinguish the principle of subsidiarity from the other two principles governing EU competences: the principles of conferral and proportionality. If the action brought on the basis of Article 8 of Protocol No 2 concerns the two latter principles, it is not admissible. 2.      Distinguishing subsidiarity from conferral and proportionality 74.      Similar to other federal systems, the European Union possesses rules of a constitutional nature which govern the right of the central level of government to act. 75.      In the European Union, those rules are set out in Article 5 TEU, which distinguishes between the principles of conferral, subsidiarity and proportionality, each having its own role to play in the division of competences between the European Union and the Member States. 76.      Without denying that there is an important interconnection between those three principles, for the purposes of assessing admissibility in this case, each of them must nevertheless be attributed its own meaning and be capable of being treated separately. 77.      Whereas there is some interpretative room to attribute to the principle of subsidiarity a broader or a narrower meaning, choosing the broader meaning would require narrowing the meaning of the other two principles. (40) Such a choice might have its advantages, as it could, for example, open wider access to the Court under Article 8 of Protocol No 2 to minorities represented in national parliaments to challenge the EU regulatory objectives to which their government agreed in the EU decision-making process, and which they could not prevent at the national level. (41) Nevertheless, finding the limits of the principle of subsidiarity must respect the meaning already attributed by the Court to the other two principles. To my mind, the existing understanding of the scope of the principles of conferral and proportionality does not leave much room for a broad interpretation of the principle of subsidiarity. 78.      To start with, in my view, the three principles enshrined in Article 5 TEU are federal principles, which aim at finding the optimal level of decision-making. The European Union was created because of the wish and the need of the Member States to establish a common level of governance to decide on issues that concern them all and transcend national boundaries. That new level of governance came into being through the conferral by the Member States of certain competences on the European Union. In other words, the European Union only has the competences that were conferred upon it in the Treaties. In that respect, the principle of conferral, as enshrined in Article 5(2) TEU, governs the existence and the limits of EU competences. 79.      The first sentence of Article 5(2) TEU states: ‘Under the principle of conferral, the Union shall act only within the limits of the competences conferred upon it by the Member States in the Treaties to attain the objectives set out therein.’ (42) 80.      The other two principles enshrined in Article 5 TEU, namely the principles of subsidiarity and proportionality, relate to the exercise, not the existence, of EU competences. (43) They come into play only when the European Union has been conferred the necessary competence. 81.      Article 5(3) TEU states: ‘Under the principle of subsidiarity, in areas which do not fall within its exclusive competence, the Union shall act only if and in so far as the objectives of the proposed action cannot be sufficiently achieved by the Member States, either at central level or at regional or local level, but can rather, by reason of the scale or effects of the proposed action, be better achieved at Union level.’ 82.      Article 5(4) TEU provides: ‘Under the principle of proportionality, the content and form of Union action shall not exceed what is necessary to achieve the objectives of the Treaties.’ 83.      For the purposes of the present case, it is important to define the meaning, purpose and scope of the principle of subsidiarity. Whatever the source of inspiration for including that principle in the EU legal system, (44) it follows from its description in Article 5(3) TEU that it clearly reflects a preference for decision-making at a lower level of government, which, for the present purposes, means at the level of the Member States rather than the European Union. (45) However, the principle of subsidiarity not only favours a lower level of decision-making, but also justifies deciding at the EU level when this is considered better. Thus, the principle of subsidiarity may function as either a limit on, or a justification for, EU level intervention. (46) 84.      Having this in mind, and taking into consideration that Article 5 TEU lists all three principles but affords them separate meanings, it is necessary to distinguish the principle of subsidiarity from the principle of conferral, on the one hand, and from the principle of proportionality, on the other. (a)    Subsidiarity vs conferral 85.      In one sense, it could be claimed that subsidiarity is a principle that justifies the creation of a common level of governance over certain issues. As such a meta principle, subsidiary motivated the choice of the competences conferred on the European Union, the number of such competences increasing with each amendment of the Treaties, and is thus inextricably linked to the principle of conferral. 86.      However, subsidiarity, as expressed in Article 5(3) TEU, is not such a meta principle, but rather an instrumental principle. (47) For that reason, the principle of subsidiarity does not concern the question as to which level of government, the European Union or the Member States, has the authority to decide on the concrete objectives of legislative action – if the European Union is given competence over a certain policy on the basis of the principle of conferral, it may set a concrete objective of legislative action in the framework of that policy. (48) Once the objective is identified, the principle of subsidiarity steps in to determine whether the European Union should act to achieve it. 87.      The principle of subsidiarity can therefore only be checked in relation to the concrete objective that was chosen by the EU legislature, and the political choice regarding what to regulate cannot be questioned through that principle. The question that the principle of subsidiarity, as defined in Article 5(3) TEU, addresses is thus not which level (European Union or Member State) can decide that something is a problem that requires regulation within the policy area for which competence is conferred on the European Union, but rather whether it is necessary that the European Union takes action to achieve the regulatory objective that it has itself considered to require regulation. 88.      In that light, the principle of subsidiarity postulates that, even if the possibility to regulate within a policy area is conferred on the European Union, and even if the need to achieve a certain concrete objective in that area by regulation is identified by the EU institutions, that still does not mean that legislative measures should be taken at the EU level. EU action is triggered only if the problem identified as requiring regulatory action could not be sufficiently resolved by Member States and the regulatory goal could be better achieved by the European Union. 89.      Furthermore, the principle of subsidiarity is applicable only in the areas of shared competences, namely areas in which the Member States have empowered the European Union to act, but did not relinquish their own competences. (49) Thus, Article 5(3) TEU restricts the assessment on the basis of the principle of subsidiarity to ‘areas which do not fall within [the European Union’s] exclusive competence’. That choice is the logical consequence of the impossibility of making a comparison as to which level is ‘better’, as the Member States have relinquished their right to act in the areas of exclusive competences in favour of the European Union. (50) 90.      The fact that the principle of subsidiarity depends on the existence of EU competence means that that principle, as set out in Article 5(3) TEU, cannot, on its own, create an EU competence. 91.      That fact also means, and this is important for the present case, that the principle of subsidiarity comes into play only if the European Union has already been conferred the relevant shared competence. That raises a question which is relevant for deciding on the admissibility of the claims in the present case: can and should the Court verify whether the European Union has competence over the regulated issue and whether such competence is shared with the Member States, even though Article 8 of Protocol No 2 only grants the Court jurisdiction to review conformity with the principle of subsidiarity? 92.      The National Assembly, supported by Hungary, favours an interpretation according to which the assessment of the existence of EU competence is a component part of the review of the principle of subsidiarity. On the contrary, the Parliament and the Council, supported by Greece, Spain and the Commission, consider that the Court cannot assess whether the European Union possesses or has exceeded the limits of its competence when examining compliance with the principle of subsidiarity. 93.      To my mind, before verifying whether the principle of subsidiarity has been complied with, the Court is empowered to establish that it is manifestly clear that the European Union has competence over the regulated issue. However, only the very basic level of control can be exercised in such a situation in which the Court can ask whether the legal basis, as specified in the act that is contested, exists in the Treaties. Furthermore, as an issue may, at the same time, pertain to several policy areas, some of which are in the European Union’s regulatory competence and others which are not, it is sufficient that the Court finds that the act in question could, prima facie, pertain to one of those policy areas over which the European Union has regulatory competence. Any further dispute about the existence or appropriateness of the legal basis is outside the reach of the principle of subsidiarity and should be resolved as a question relating to the principle of conferral. Such a dispute cannot be submitted to the Court under an action based on Article 8 of Protocol No 2. 94.      Likewise, a claim that the contested act exceeds the limits of a particular EU competence as conferred by the Treaties is also a question of the existence of the competence. It is thus a question relating to the principle of conferral, and not one relating to the principle of subsidiarity. 95.      The case-law has already treated such questions as questions of the principle of conferral, rather than subsidiarity. To take a classic example, in Tobacco Advertising, (51) the Court considered, as a matter of conferral, that there are limits to the internal market competence, today in Article 114 TFEU, and that the European Union can, and even must, take into consideration a high level of protection of human health, over which it does not have regulatory competence, when legislating within the limits of that competence. However, the choice to harmonise tobacco advertising was not, and could not, be challenged as such, as long as it was within the limits of the internal market competence. In that sense, that case-law prevents reliance on the principle of subsidiarity to challenge the fact that the choice of the concrete legislative act was made at the EU level rather than on the national level, as long as that choice is within the limits of a competence as conferred on the European Union. 96.      Finally, when faced with a claim alleging breach of the principle of subsidiarity, the Court can verify whether the act in question, on the basis of the stated legal basis, does not pertain to an area of exclusive EU competence. That task is today facilitated by the express enumeration of EU exclusive competences in Article 3 TFEU, but that kind of question is not raised by the present case. (b)    Subsidiarity vs proportionality 97.      Issues pertaining to the principle of subsidiarity also have to be distinguished from those pertaining to the principle of proportionality. 98.      As defined in Article 5(4) TEU, the principle of proportionality asks whether, once it is established that action at the EU level is warranted because the Member States acting alone cannot sufficiently achieve the regulatory objective set by the European Union, the concrete measures chosen are appropriate and necessary. Thus, the proportionality review addresses the content of an EU act, not the appropriate level of decision-making. (52) As confirmed by case-law, the appropriateness and necessity of a measure are assessed in relation to the concrete regulatory objective chosen at the EU level. (53) 99.      I sympathise with arguments that it could be in the interest of national parliaments to challenge EU legislation on proportionality grounds. The practice of the early warning mechanism demonstrates that indeed they do (see point 71 of the present Opinion). For instance, it is in the interest of national parliaments to have less intrusive measures, or even no measures at all, at the EU level, since this leaves more room for the national political process. 100.  The usefulness of arguments about the content of EU measures could indeed be a reason why such arguments, although they do not concern the principle of subsidiarity, are nevertheless taken into consideration by the Commission in the context of the early warning mechanism. 101. Nevertheless, the principle of subsidiarity enshrined in Article 5(3) TEU is not envisaged by the Treaties to encompass questions relating to the principle of proportionality under Article 5(4) TEU. 102. That is clear, since, although Protocol No 2 concerns both the principles of subsidiarity and proportionality, Article 8 of Protocol No 2 limits actions brought by national parliaments to the principle of subsidiarity, thus excluding issues pertaining to the principle of proportionality. 103. Therefore, claims that challenge the appropriateness, usefulness, intensity or similar aspects of the chosen EU legislative measures are claims pertaining to the principle of proportionality and cannot be brought before the Court on the basis of Article 8 of Protocol No 2. 104. To sum up, an action brought by a national parliament under Article 8 of Protocol No 2 is limited to the principle of subsidiarity. The only claims to be treated as a matter of subsidiarity are those that contend that the objective of a legislative act, as considered important by the European Union, does not need regulatory action at the EU level, as the Member States can achieve that objective sufficiently when acting on their own and the European Union cannot achieve it better. 105. The Court should treat as a matter of the principle of conferral (Article 5(2) TEU), claims that the European Union does not have competence over certain issues, or that the measure has superseded the scope of an EU competence, and as a matter of the principle of proportionality (Article 5(4) TEU), claims that the proclaimed objective of a legislative act does not need regulating, or that the chosen measures are inadequate or impose unnecessary burdens on Member States or individuals. Such claims do not pertain to the principle of subsidiarity. To challenge those issues, the National Assembly would have to go through the fourth paragraph of Article 263 TFEU, (54) and cannot rely on an action based on Article 8 of Protocol No 2. 106. It is in that light that I will now turn to the assessment of the admissibility of the National Assembly’s claims in the present case. 3.      Assessment in the present case 107. For the purposes of assessing the admissibility of the claims put forward by the National Assembly in the present case, it is necessary, on the basis of the foregoing considerations, to decide which of them concern the principle of subsidiarity and which do not. 108. First, the principle of subsidiarity is applicable in the present case, as the policy area of asylum and immigration is conferred on the European Union as one of the shared competences, (55) and Article 78(2)(e) TFEU and Article 79(2)(a), (b) and (c) TFEU, specified as the legal bases of Regulation 2024/1351, allow for EU legislative action. Any further inquiry beyond such a prima facie conclusion would exceed the jurisdiction of the Court under Article 8 of Protocol No 2. 109. Second, it is for the European Union to decide that legislative action is needed to alleviate the burden on those Member States that are under migratory pressure. That choice cannot be questioned as a matter of the principle of subsidiarity. That principle is only relevant for the question whether that legislative objective can be sufficiently achieved by Member States acting alone or it can be better achieved by EU legislative measures. 110. Third, I agree with the Parliament and the Council, supported by Greece, Spain and the Commission, that the first four claims put forward by the National Assembly (see points 21 to 28 of the present Opinion) do not concern the principle of subsidiarity. 111. The first and second claims, which allege that Article 72 TFEU and Article 4(2) TEU, respectively, reserve the competence to maintain law and order and ensure national security to the Member States, relate to the principle of conferral, and not to the principle of subsidiarity. By those claims, the National Assembly essentially argues that the European Union was not conferred competence to adopt Regulation 2024/1351. Such claims cannot be heard by the Court on the basis of Article 8 of Protocol No 2. 112. The third claim concerns the alleged harmful financial consequences of the mandatory solidarity mechanism introduced by Regulation 2024/1351, and thus, in essence, as indicated by the Parliament and the Commission, alleges that the EU measure is not proportionate. Furthermore, the alleged infringement of Article 151 TFEU seems to contend that the repercussions of measures required under Regulation 2024/1351 for national budgets would make it impossible for France to fulfil its social policy obligations contrary to Article 151 TFEU. That argument does not question the appropriate level of decision-making and therefore does not pertain to subsidiarity. 113. The fourth claim, regarding the usefulness of the relocation regime, relates, according to the Parliament and the Commission, to the principle of proportionality. To my mind, that claim could be understood in one of two ways. It either contests the appropriateness of the relocation regime to achieve the objective of Regulation 2024/1351, which is, inter alia, to provide effective support to Member States under migratory pressure, (56) in which case it is an argument of proportionality; or it challenges the very objective of that legislation, in which case it may be considered to relate to the principle of conferral, denying the existence of the competence of the European Union to choose such an objective. Either way, that claim does not concern the principle of subsidiarity. 114. In any event, as the National Assembly concludes with the argument that the relocation regime, not being provided for in Title V of the FEU Treaty, exceeds the competences of the European Union, it seems that it puts forward an argument that is related to the principle of conferral and not to the principle of subsidiarity. 115. I therefore propose to the Court to reject those four claims as inadmissible under Article 8 of Protocol No 2. 116. In contrast, as indicated by the Parliament and the Council, supported by Greece, Spain and the Commission, the fifth claim put forward by the National Assembly does concern the principle of subsidiarity and is therefore admissible. 117. I will now assess the merits of that claim. C.      Substance 118. To recall, by its fifth claim, the National Assembly submits that there is nothing to indicate that the Member States would not have been able, either alone or in cooperation, and more effectively than the European Union, to manage the problems caused by the mass influx of applicants for international protection. 1.      Procedural and substantive subsidiarity 119. As the Court has explained, in the context of judicial review of an EU act for compliance with the principle of subsidiarity, the EU judicature must verify ‘both compliance with the substantive conditions set out in Article 5(3) TEU and compliance with the procedural safeguards provided for by [Protocol No 2]’. (57) 120. First, procedural subsidiarity requires that the EU institutions provide sufficient reasons why they considered that action at the EU level is required. The Court has focused on compliance with formal requirements and in particular a statement of reasons, invoking settled case-law to the effect that respect for the obligation to state reasons must be evaluated not only by reference to the wording of the contested act, but also by reference to its context and the circumstances of the individual case. The Court has found that those requirements are complied with where the relevant legislative materials include sufficient information showing clearly and unequivocally the advantages of taking action at the EU level rather than at the Member State level. (58) That has been so even if there was no express reference to subsidiarity in the EU act concerned. (59) 121. Second, substantive subsidiarity concerns the question, as set out in Article 5(3) TEU, whether the EU institutions were entitled to conclude that the objective of the proposed action cannot be sufficiently achieved by the Member States and can be better achieved, by reason of its scale or effects, at the EU level. (60) 122. On the basis of the wording of Article 5(3) TEU, it is generally considered that the subsidiarity test has two components: negative and positive, which, however, as Advocate General Kokott considered, ‘ultimately address a single question from two different angles, namely whether action should be taken at Union level or at national level in order to achieve the envisaged objectives’. (61) 123. In the case-law, much, but not all, of which has concerned internal market harmonisation under Article 114 TFEU, the Court has found that the principle of subsidiarity has been complied with, essentially on the grounds that such harmonisation predicates EU-level action. (62) 124. Scholars consider that such an assessment of the principle of subsidiarity is not satisfactory, as it empties the judicial review of any real meaning. (63) If it is sufficient that the EU legislature simply declares that harmonisation can be better achieved at the EU level, without explaining what is to be achieved by harmonisation in the first place, the subsidiarity test would always allow for action at the EU level, as it is clear that it is not likely that the Member States alone would arrive at identical solutions. 125. I agree with such criticism. Indeed, harmonisation should not be considered as the objective of legislation, but rather as a possible tool to achieve the desired goal. As a matter of internal market policy, a goal may be the elimination of obstacles to cross-border trade, or removal of appreciable distortions of competition. (64) It should thus be for the EU legislature to establish that barriers exist and then demonstrate, as a matter of subsidiarity, that the best way to eliminate them is by the adoption of harmonisation measures. 126. There are also examples from the case-law in which the EU legislature has provided for more substantive justifications for the preference for action at the EU level, which the Court has accepted. (65) 127. In any case, where the EU measure in question has the aim of resolving problems with a cross-border dimension, there is, as stated by Advocate General Kokott, ‘a strong presumption of added value for action at Union level’. (66) 128. A related question is whether the comparison is to be performed between action by the European Union in relation to the Member States acting alone, or, as suggested by the National Assembly, in relation to Member States acting in cooperation. 129. In that respect, I agree with the Commission that comparison with the capacity of the Member States to sufficiently address the legislative aim of the measure when cooperating outside of the framework of the European Union does not make sense. The European level of decision-making was created precisely in order to enable Member States to address common issues together by means of the decision-making processes envisaged by the Treaties. If there is a need for common action, that action should be undertaken at the EU level. Cooperating outside of the framework of EU law, in an international setting, is justified only when the competence to address an issue, which cannot be resolved by Member States acting alone, is not conferred on the European Union. Additionally, the procedures at the level of the European Union are democratically legitimised through the Council and the Parliament. That makes them preferable to different forms of intergovernmental cooperation among the Member States. 130. The appropriate comparator for the subsidiarity test is therefore Member States acting on their own; (67) however, all Member States should be taken into consideration. In that respect, the Court has held that ‘the subsidiarity principle is not intended to limit the EU’s competence on the basis of the situation of any particular Member State taken individually, but requires only that the proposed action can, by reason of its scale or effects, be better achieved at the EU level. (68) It follows that the principle of subsidiarity ‘cannot have the effect of rendering an EU measure invalid because of the particular situation of a Member State, even if it is more advanced than others in terms of an objective pursued by the EU legislature.’ (69) 131. In sum, procedural and substantive subsidiarity clarify what is required from the EU institutions involved in the decision-making process in order to justify action at the EU level in the light of the principle of subsidiarity. However, that still does not resolve the issue of the intensity of the Court’s review. 2.      The intensity of judicial review of subsidiarity 132. In substantive terms, as explained, the principle of subsidiarity requires that the EU institutions assess whether action at the Member State level is indeed insufficient and action at the EU level is better, or, stated in simpler terms, whether such EU action has clear benefits. (70) 133. In my understanding, the conclusion which the EU institutions reach in that respect must, in principle, be accepted by the Court if they can demonstrate its rationality. In other words, what the Court should ask is whether it is clearly obvious (manifest) that the institutions could not reach that conclusion. (71) That is so because the Court cannot substitute its assessment for that of the institutions, without entering into the sphere of political choices. 134. Choosing the intensity of judicial review is a matter of judicial policy. As recognised by scholars: ‘If the CJEU continues with light touch review, it will be open to the criticism that it is effectively denuding the obligation in Article 5(3) [and] (4) [TEU] of all content. If, by way of contrast, the CJEU takes a detailed look at the evidence underlying the Commission’s claim it will have to adjudicate on what may be a complex socio-economic calculus concerning the most effective level of government for different regulatory tasks.’ (72) 135. In my view, performing only a light review based on the rationality of the reasons offered in favour of action at the EU level would allow the Court to avoid substituting its decision for that of the legislature, but, at the same time, would make the legislature take subsidiarity seriously. (73) 136. To achieve both aims, the procedural aspect of subsidiarity becomes important. The Court must insist that institutions duly explain their assessment. That explanation should not be given in formulas, but should be adjusted to the particularities of each legislative action. (74) Such a ‘tailor made’ justification, on the one hand, forces the institutions to meaningfully assess whether the European Union must act in a concrete situation, and, on the other hand, allows the Court to decide whether EU action seems reasonably required. (75) 137. On the basis of the foregoing, it remains to be assessed whether the introduction of the mandatory solidarity mechanism by Regulation 2024/1351 infringes the principle of subsidiarity, as claimed by the National Assembly. 3.      Assessment in the present case 138. When an EU act further develops existing EU legislation, as is the case for Regulation 2024/1351, with a view to addressing problems left by that legislation, that seems to call for action to be taken at the EU level. That is so especially when those problems are the result of the lack of sufficient action at the national level. 139. In that sense, given that existing EU legislation did not provide for the fair sharing of responsibility, as required by Article 80 TFEU, the introduction of a mandatory solidarity mechanism seems justified in order to achieve the legislative objective to help Member States under migratory pressure. Such an obligation can only be introduced at the EU level. 140. Regulation 2024/1351 as well as related documents provide such reasons, which allow the Court to conclude that that regulation complies with the principle of subsidiarity. 141. To begin with, recital 88 of Regulation 2024/1351 states in the relevant part: ‘Since the objectives of this Regulation, namely the establishment of criteria and mechanisms for determining the Member State responsible for examining an application for international protection registered in one of the Member States by a third-country national or a stateless person, and the establishment of a solidarity mechanism to support Member States in addressing situations of migratory pressure, cannot be sufficiently achieved by the Member States but can rather, by reason of the scale and effects, be better achieved at Union level, the Union may adopt measures, in accordance with the principle of subsidiarity as set out in Article 5 [TEU]’. 142. Even if that recital is largely a formulistic statement of subsidiarity, it is further elaborated in the Commission’s proposal for that regulation. (76) In a specific section on subsidiarity in that proposal, the Commission indicates that: ‘This proposal streamlines the current rules set out in [Regulation No 604/2013] and aims at ensuring the correct application of these rules which will limit unauthorised movements of third-country nationals between Member States, issues which are cross-border by nature. These rules are complemented with a new solidarity mechanism to put in place a system to address situations where Member States are faced with migratory pressure. … Achievement of these objectives requires action at the EU level since they are cross-border by nature. It is clear that actions taken by individual Member States cannot satisfactorily reply to the need for a common EU approach to a common problem.’ (77) 143. Additionally, that proposal includes a discussion of the evidence gathered by the Commission regarding the current problems with the EU asylum and migration system, including inadequacies at the Member State level. It states, among other things, that: ‘The challenges of migration management, ranging from ensuring a balance of efforts in dealing with asylum applications to ensuring a quick identification of those in need of international protection or effective return of those who are not in need of protection, should not have to be dealt with by individual Member States alone, but by the EU as a whole. In addition, the strain on Member States’ asylum systems continues to put a heavy burden on Member States of first arrival as well as on the asylum systems of other Member States through authorised movements. The current migration system is insufficient in addressing those realities. In particular, there is currently no effective solidarity mechanism in place and no efficient rules on responsibility. A European framework that can manage the interdependence between Member States’ policies and decisions is therefore required. This framework must take into account the ever-changing realities of migration, which have meant increased complexity and an intensified need for coordination.’(78) 144. While there was no impact assessment carried out by the Commission, there was one made by the Parliament, (79) finding that, as regards the proposal for Regulation 2024/1351, the principle of subsidiarity was complied with, calling it ‘a common approach to a common European problem’. Specifically, that study indicated: ‘The current unequal burden on Member States, inadequate and … poorly recognised distribution mechanisms for applicants for international protection, and insufficient control of secondary movements, are problems that are cross-border by nature. Accordingly, Member States cannot address these challenges alone, and the EU has a right to act.’ (80) 145. It might be added that, starting long before Regulation 2024/1351, the emergence and development of a common EU policy on asylum and immigration has been justified in the light of the principle of subsidiarity. Older as well as more recent policy documents would seem to lend further support for substantiating the need for the adoption of that regulation. 146. To mention just a few: –        According to the European Parliament’s 1986 Resolution on the drawing up of a common European policy on refugees: ‘it is both natural and desirable to seek a common solution to the serious problems facing the Member States experiencing difficulties in accommodating the relatively high number of refugees applying to them in order to avoid “exporting” the problems from one Member State to another, since such a “pass the parcel” situation is humiliating both for the refugees and for our free and democratic societies’.(81) –        In the Commission’s 1991 Communication on immigration, it is stated: ‘Each country, with its own history, its own traditions and its own peculiar geographical situation, tends to take the line it thinks most appropriate. The problem is, though, that whatever one country does may affect the situation in the others’; and: ‘It is the Community’s duty to act to prevent such perverse effects, which would hinder the achievement of objectives set out in the Single Act. This had led the Member States to recognise the need for a common approach by the Twelve and to discuss ways in which they can cooperate. The interdependence of various national situations, taken together with the permeability of borders, requires joint action, if only on grounds of efficiency.’(82) –        According to the Commission’s 1994 Communication on immigration and asylum policies: ‘There is increased recognition that the issues involved need to be tackled on a cooperative basis. That has found expression in the provisions of the Treaty on European Union which formally designates the subjects as being matters of common interest, to be addressed in the context of a single institutional framework. That is as it should be. The deepening of the European integration process calls for an integrated and coherent response, which combines realism with solidarity, to the challenges which migration pressures and the integration of legal immigrants pose for the Union as a whole. Failure to meet those challenges would be to the detriment of attempts to promote cohesion and solidarity within the Union and could, indeed, endanger the future stability of the Union itself.’(83) –        In the Commission’s 2011 Communication on enhanced intra-EU solidarity in the field of asylum, it is stated: ‘Solidarity has been recognised as an essential component of the Common European Asylum System (CEAS) since the outset. The need to translate solidarity into concrete measures flows from practical realities since the asylum systems of all Member States are interdependent. An overburdened or malfunctioning system in one Member State has a clear impact on all the others, including through secondary movements.’ (84) –        The Commission’s 2026 European Asylum and Migration Management Strategy explains that: ‘With the Pact, the EU is putting in place an effective system of solidarity and responsibility to collectively manage migration, where no Member State is left alone under pressure.’(85) 147. To my mind, the findings and statements in Regulation 2024/1351 itself and in other documents cited sufficiently satisfy both procedural and substantive subsidiarity. The reasons provided for acting at the EU level do not seem unreasonable and the National Assembly has not put forward any arguments to invalidate such a finding. 148. Therefore, I propose to the Court to reject the National Assembly’s claim relating to the principle of subsidiarity as unfounded. VI.    Costs 149. Under Article 138(1) of the Rules of Procedure of the Court of Justice, the unsuccessful party is to be ordered to pay the costs if they have been applied for in the successful party’s pleadings. In the present case, since the Parliament and the Council have applied for costs and the National Assembly has been unsuccessful, the National Assembly should be ordered to bear its own costs and to pay those incurred by the Parliament and the Council. 150. Pursuant to Article 140(1) of those rules, the Member States and EU institutions which have intervened in the proceedings are to bear their own costs. Accordingly, Greece, Spain, Hungary and the Commission must bear their own costs. VII. Conclusion 151. On the basis of the foregoing, I propose that the Court should: (1)      dismiss the action as partly inadmissible and partly unfounded; (2)      order the National Assembly to bear its own costs and to pay those incurred by the Council of the European Union and the European Parliament; and (3)      order the Hellenic Republic, the Kingdom of Spain, Hungary and the European Commission to bear their own costs. 1      Original language: English. 2      The National Assembly is the lower house of the French Parliament comprising 577 deputies, while the upper house is the Sénat (Senate), with 348 senators. In the present case, the application was made by the National Assembly at the request of Ms Marine Le Pen and 87 deputies. 3      (OJ 2016 C 202, p. 206; ‘Protocol No 2’). That protocol is annexed to the TEU and the FEU Treaty. 4      Regulation of the European Parliament and the Council of 14 May 2024, amending Regulations (EU) 2021/1147 and (EU) 2021/1060 and repealing Regulation (EU) No 604/2013 (OJ L, 2024/1351). 5      See the second and third paragraphs of Article 88-6 of the Constitution of 4 October 1958, as amended by Constitutional Law No 2008-724 of 23 July 2008 on the modernisation of the institutions of the Fifth Republic (JORF of 24 July 2008, p. 11890). 6      As mentioned in point 7 of the present Opinion, the National Assembly requests the annulment of Regulation 2024/1351 in its entirety, and its partial annulment only in the alternative. However, all of the parties to these proceedings, including the National Assembly, agree that Part IV of that regulation is not severable from the rest of it. Therefore, the claim for partial annulment could be dismissed as inadmissible at the outset, and the present action understood as seeking the annulment of the entire regulation. 7      See Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions on a New Pact on Migration and Asylum, COM(2020) 609 final, 23 September 2020. For the list of measures, see the Commission’s website, available at: https://home-affairs.ec.europa.eu/policies/migration-and-asylum/pact-migration-and-asylum_en. 8      For a general commentary, see, for example, Peers, S., ‘The New Asylum Pact: Brave New World or Dystopian Hellscape?’, European Journal of Migration and Law, Vol. 26, 2024, p. 381. 9      See Articles 3 to 15 and recitals 1 to 21 of Regulation 2024/1351. 10      Regulation of the European Parliament and of the Council of 26 June 2013 establishing the criteria and mechanisms for determining the Member State responsible for examining an application for international protection lodged in one of the Member States by a third-country national or a stateless person (OJ 2013 L 180, p. 31). 11      See Articles 16 to 55 and recitals 36 to 76 of Regulation 2024/1351. 12      See Articles 56 to 71 and recitals 22 to 35 of Regulation 2024/1351. The concept of ‘migratory pressure’ is defined in Article 2(24) thereof. 13      See Article 56(1) and recital 29 of Regulation 2024/1351. 14      According to Article 2(22) of Regulation 2024/1351, ‘relocation’ is defined as ‘the transfer of an applicant or a beneficiary of international protection from the territory of the benefitting Member State to the territory of a contributing Member State’. Article 2(19) and (20) of that regulation, in turn, defines the ‘benefitting Member State’ as the one benefitting from solidarity contributions, and the ‘contributing Member State’ as the one ‘that provides or is obliged to provide solidarity contributions to a benefitting Member State’, as set out in Part IV thereof. 15      See Article 57(4) of Regulation 2024/1351. 16      See Article 67(2), (3) and (7) to (9) of Regulation 2024/1351. 17      See Article 68(3) of Regulation 2024/1351. 18      Article 72 TFEU states: ‘This Title [Title V on the area of freedom, security and justice] shall not affect the exercise of the responsibilities incumbent upon Member States with regard to the maintenance of law and order and the safeguarding of internal security.’ 19      Article 4(2) TEU states: ‘The Union shall respect the equality of Member States before the Treaties as well as their national identities, inherent in their fundamental structures, political and constitutional, inclusive of regional and local self-government. It shall respect their essential State functions, including ensuring the territorial integrity of the State, maintaining law and order and safeguarding national security. In particular, national security remains the sole responsibility of each Member State.’ 20      For a detailed discussion, see, for example, Kiiver, P., The Early Warning System for the Principle of Subsidiarity  Constitutional theory and empirical reality, Routledge Publishing, London, 2012; Granat, K., The Principle of Subsidiarity and its Enforcement in the EU Legal Order  The Role of National Parliaments in the Early Warning System, Hart Publishing, Oxford, 2018. 21      See, in that respect, Protocol (No 1) on the role of national parliaments in the European Union, annexed to the TEU, the FEU Treaty and the Treaty establishing the European Atomic Energy Community (OJ 2016 C 202, p. 203), as well as Article 4 of Protocol No 2. 22      Such a reasoned opinion is to be submitted within eight weeks from the date of transmission of a legislative proposal to national parliaments and thus before the adoption of legislative acts at the EU level. See, in particular, Articles 6 and 7 of Protocol No 2. 23      That seems to follow not only from the wording of the provisions of Protocol No 2, which do not link the two procedures together, but also from the preparatory documents, dating back to the Convention on the Future of Europe (‘the European Convention’), in which proposals to link the two procedures appear to have been raised and rejected. See, for example, CONV 286/02, 23 September 2002, pp. 7 and 8; CONV 331/02, 11 October 2002, p. 8; CONV 353/02, 22 October 2002, p. 11; CONV 579/03, 27 February 2003, p. 3. 24      It is worth noting that, as indicated by the Commission, three national parliaments from Italy, Hungary and Slovakia submitted reasoned opinions regarding non-compliance of the proposal for Regulation 2024/1351 with the principle of subsidiarity, while six national parliaments from Germany, Greece, Spain, Malta, Portugal and Romania submitted contributions on that proposal, several of which indicated that that principle had been respected. For a list of documents, see the website of IPEX.eu (which is the interparliamentary platform for exchange of EU information between national parliaments and the European Parliament), available at: https://ipex.eu/IPEXL-WEB/document/COM-2020-0610, and the European Parliament legislative observatory, available at: https://oeil.europarl.europa.eu/oeil/en/procedure-file?refernece= 2020/0279(COD). 25      See, for example, judgments of 12 November 2015, Elitaliana v Eulex Kosovo (C‑439/13 P, EU:C:2015:753, paragraph 37); of 6 October 2020, Bank Refah Kargaran v Council (C‑134/19 P, EU:C:2020:793, paragraph 25); and of 6 July 2023, EIB and Commission v ClientEarth (C‑212/21 P and C‑223/21 P, EU:C:2023:546, paragraph 48). 26      The second paragraph of Article 8 of Protocol No 2, which concerns the Committee of the Regions, reads: ‘In accordance with the rules laid down in the said Article, the Committee of the Regions may also bring such actions against legislative acts for the adoption of which the [FEU Treaty] provides that it be consulted.’ 27      See, in that sense, Article 19(3) TEU and Articles 258 to 272 TFEU, conferring on the Court of Justice of the European Union, as an institution, jurisdiction to hear different types of direct actions and to give preliminary rulings. Only Article 269 TFEU and Article 273 TFEU refer to the Court of Justice with regard to actions relating to acts adopted under Article 7 TEU and disputes between Member States under special agreements, respectively. 28      Article 256(1) TFEU provides: ‘The General Court shall have jurisdiction to hear and determine at first instance actions or proceedings referred to in Articles 263, 265, 268, 270 and 272, with the exception of those assigned to a specialised court set up under Article 257 and those reserved in the Statute for the Court of Justice. The Statute may provide for the General Court to have jurisdiction for other classes of action or proceeding.’ 29      See, in that regard, Article 50a of the Statute, granting jurisdiction to the General Court to hear at first instance disputes between the European Union and its servants (staff cases), along with Article 50b thereof, transferring to that Court jurisdiction to give preliminary rulings in certain specific areas. 30      See, in that respect, Kiiver, cited in footnote 20 of the present Opinion, p. 46, considering that Article 8 of Protocol No 2 ‘is simply a lex specialis of Article 263 TFEU’. 31      In its transmittal letter, the French Government indicated, in particular, that Article 8 of Protocol No 2 establishes a specific remedy, whereby a national parliament or a chamber thereof may bring an action before the Court for breach of the principle of subsidiarity by a legislative act, which is one of the ‘other cases provided for in the Treaties’ within the meaning of Article 19(3)(c) TEU in which the Court has jurisdiction to rule. According to that government, it therefore follows expressly from Article 8 of Protocol No 2 that the parliament or chamber brings the action in its own name, which is further supported by the context and origins of that provision. 32      As set out in the second paragraph of Article 263 TFEU, those grounds are ‘lack of competence, infringement of an essential procedural requirement, infringement of the Treaties or of any rule of law relating to their application, or misuse of powers’. 33      See Article 5(2) to (4) TEU, defining the principles of conferral, subsidiarity and proportionality, respectively, as principles that, as explained in Article 5(1) TEU, govern the limits and the use of EU competences. 34      It is worth noting that other provisions of the Treaties also mention national parliaments as having a role only in relation to subsidiarity. See, for example, Article 12(b) TEU, Article 69 TFEU and Article 352(2) TFEU. 35      See, for example, CONV 286/02, 23 September 2002, p. 6; CONV 724/01/03, 28 May 2003, p.142. 36      See, for example, CONV 286/02, 23 September 2002, pp. 7 to 9; CONV 331/02, 11 October 2002, p. 9; CONV 579/03, 27 February 2023, pp. 2 and 3; CONV 797/03, 10 June 2003, p. 51. 37      See, in that respect, Baraník, K, Subsidiarity: Mechanisms for monitoring compliance, European Parliamentary Research Service, PE 775.868  July 2025, p. 20. 38      See, for example, judgments of 9 October 2001, Netherlands v Parliament and Council (C‑377/98, ‘Biotechnology’, EU:C:2001:523) (claims concerning the legal basis and the principle of subsidiarity); of 18 June 2015, Estonia v Parliament and Council (C‑508/13, EU:C:2015:403) (claims concerning the principles of subsidiarity and proportionality); and of 4 May 2016, Poland v Parliament and Council (C‑358/14, EU:C:2016:323) (claims concerning the legal basis and the principles of subsidiarity and proportionality). The same is true when the validity of an EU act is challenged through the preliminary ruling procedure. See, for example, judgments of 8 June 2010, Vodafone and Others (C‑58/08, EU:C:2010:321) (claims concerning the legal basis and the principles of subsidiarity and proportionality), and of 22 November 2018, Swedish Match (C‑151/17, EU:C:2018:938) (claims concerning the principles of subsidiarity and proportionality). 39      Thus, for example, the Court could have blurred the distinction between the principles of subsidiarity and proportionality in paragraph 184 of the judgment of 10 December 2002, British American Tobacco (Investments) and Imperial Tobacco (C‑491/01, EU:C:2002:741), without exceeding the boundaries of its jurisdiction in that case. 40      See, for example, Schütze, R., ‘Subsidiarity after Lisbon: Reinforcing the Safeguards of Federalism’, Cambridge Law Journal, Vol. 68, 2009, p. 525, in particular p. 533, who proposes that subsidiarity should be treated as federal proportionality and thus be used to examine whether the EU act disproportionately restricts national autonomy. That, however, requires interpreting the principle of proportionality narrowly as limited to examining whether an EU act disproportionally limits individual rights. 41      Arguably, this can even be seen as one of the justifications for the federal organisation of the European Union. See, in that respect, Moussa, M., Federal Impartiality Navigating Divisive Rights in the EU and the US, Hart Publishing, Oxford, 2026. 42      Additionally, the second sentence of Article 5(2) TEU, as well as Article 4(1) TEU, clarify that competences not conferred upon the European Union remain with the Member States. 43      Article 5(1) TEU states: ‘The limits of Union competences are governed by the principle of conferral. The use of Union competences is governed by the principles of subsidiarity and proportionality.’ 44      For a discussion of the origins of the principle of subsidiarity and the genesis of that principle within the text of the Treaties, see, for example, Schütze, R., From Dual to Cooperative Federalism The Changing Structure of European Law, Oxford University Press, Oxford, 2009, pp. 243 to 256; Granat, cited in footnote 20 of the present Opinion, pp. 9 to 43; Fabbrini, F., ‘The Principle of Subsidiarity’, in Schütze, R. and Tridimas, T. (eds), Oxford Principles of European Union Law Volume I: The European Union Legal Order, Oxford University Press, Oxford, 2018, p. 221. 45      I note that, as compared to the former second paragraph of Article 5 EC, as part of the changes introduced by the Lisbon Treaty, Article 5(3) TEU refers to ‘either at central level or at regional and local level’ in connection with the Member States, thus also recognising the subnational levels of decision-making. 46      See, in that respect, Halberstam, D., ‘Comparative Federalism and the Role of the Judiciary’, in Caldeira, G.A., Kelemen, D. and Whittington, K.E. (eds), The Oxford Handbook of Law and Politics, Oxford University Press, Oxford, 2008, p. 142, in particular p. 152. 47      In that sense, Halberstam distinguishes between instrumental and substantive subsidiarity. See Halberstam, cited in footnote 46 of the present Opinion, in particular pp. 152 to 154. 48      If the legal basis for legislative action within a certain policy area itself sets objectives for the achievement of which the European Union may act, a concrete legislative proposal must respect such limits; otherwise, it infringes the principle of conferral. 49      Some competences have been conferred on the European Union as exclusive competences, which means that Member States can no longer legislate in those areas even if the European Union did not legislate. See, in that respect, Article 2(1) TFEU. The exclusive competences are exhaustively enumerated in Article 3 TFEU. Other competences are shared between the European Union and the Member States and, as stated in Article 2(2) TFEU, in those areas the Member States can exercise their competence to the extent that the European Union has not exercised its competence. The policies in which the European Union and the Member States share competence are listed, albeit not exhaustively, in Article 4(2) TFEU. 50      That still does not mean that the European Union must regulate issues that pertain to the exclusive competences; however, the question whether or not to regulate is a political choice not limited by the principle of subsidiarity. 51      See judgment of 5 October 2000, Germany v Parliament and Council (C‑376/98, ‘Tobacco Advertising’, EU:C:2000:544, in particular paragraphs 84 and 85). See also Opinion of Advocate General Kokott in Poland v Parliament and Council (C‑358/14, EU:C:2015:848, points 143 and 144) (distinguishing the legal basis requirement, in casu internal market harmonisation under Article 114 TFEU, from the principle of subsidiarity). 52      See, for example, Opinion of Advocate General Léger in United Kingdom v Council (C‑84/94, ‘Working Time’, EU:C:1996:93, points 125 to 127) (distinguishing the principles of subsidiarity and proportionality as operating at different levels of EU action). 53      See judgment of 10 December 2002, British American Tobacco (Investments) and Imperial Tobacco (C‑491/01, EU:C:2002:741, paragraph 122): ‘the principle of proportionality, which is one of the general principles of [EU] law, requires that measures implemented through [EU] provisions should be appropriate for attaining the objective pursued and must not go beyond what is necessary to achieve it.’ See also, for example, judgment of 4 May 2016, Poland v Parliament and Council (C‑358/14, EU:C:2016:323, paragraph 78). 54      In that case, however, the action at first instance would have to be lodged before the General Court. 55      See, in that respect, Chapter 2, entitled ‘Policies on border checks, asylum and immigration’, which is part of Title V of the FEU Treaty on the area of freedom, security and justice. Article 4(2)(j) TFEU lists the area of freedom, security and justice among the shared competences. 56      See recitals 22 and 88 of Regulation 2024/1351. 57      Judgment of 4 May 2016, Poland v Parliament and Council (C‑358/14, EU:C:2016:323, paragraph 113). 58      See, for example, judgment of 4 May 2016, Poland v Parliament and Council (C‑358/14, EU:C:2016:323, paragraphs 122 and 123). 59      See judgments of 13 May 1997, Germany v Parliament and Council (C‑233/94, EU:C:1997:231, in particular paragraph 28), and Biotechnology (paragraph 33). 60      See, for example, judgment of 4 May 2016, Poland v Parliament and Council (C‑358/14, EU:C:2016:323, paragraph 114). 61      Opinion of Advocate General Kokott in Poland v Parliament and Council (C‑358/14, EU:C:2015:848, point 142). 62      See, for example, judgments of 12 November 1996, United Kingdom v Council (C‑84/94, ‘Working Time’, EU:C:1996:431, paragraphs 47 and 55) (harmonisation ‘presupposes’ EU-wide action); Biotechnology (paragraph 32) (given effects on intra-EU trade, it is clear that objective better achieved by the European Union); of 10 December 2002, British American Tobacco (Investments) and Imperial Tobacco (C‑491/01, EU:C:2002:741, paragraphs 180 to 183) (harmonisation calls for action at the EU level); and of 22 May 2003, Commission v Germany (C‑103/01, EU:C:2003:301, paragraph 47) (harmonisation of divergent provisions can be undertaken only by the EU legislature). 63      See, for example, Weatherill, S., The Internal Market as a Legal Concept, Oxford University Press, Oxford, 2017, p. 176; Davies, G., ‘The Working Time Case and the Death of Subsidiarity’, in Craig, P. and Schütze, R. (eds), Landmark Cases in EU Law, Volume 1: The Constitutional Cases, Hart Publishing, Oxford, 2025, p. 145. 64      See, for example, Tobacco Advertising (paragraph 95). 65      See, for example, judgments of 8 June 2010, Vodafone and Others (C‑58/08, EU:C:2010:321, paragraphs 76 to 79) (given interdependence of charges, joint approach best achieved at the EU level), and of 4 May 2016, Poland v Parliament and Council (C‑358/14, EU:C:2016:323, paragraphs 116 to 118) (given interdependence of objectives of internal market and public health, best achieved at the EU level). 66      Opinion of Advocate General Kokott in Poland v Parliament and Council (C‑358/14, EU:C:2015:848, point 164). See also Opinion of Advocate General Poiares Maduro in Vodafone and Others (C‑58/08, EU:C:2009:596, point 33). The transnational aspects of the issue under consideration have been considered an important indicator that action at the EU level is justified ever since the Edinburgh Guidelines. See European Council, Conclusions of the Presidency adopted at Edinburgh, 11-12 December 1992, Annex 1 to Part A: Overall Approach to the Application by the Council of the Subsidiarity Principle and Article 3b of the Treaty on European Union, p. 19. 67      See Biotechnology (paragraph 32), in which the Court referred to ‘action taken by the Member States alone’. See also, for example, Gutman, K., The Constitutional Foundations of European Contract Law: A Comparative Analysis, Oxford University Press, Oxford, 2014, pp. 302, 303 and 351. 68      Judgment of 18 June 2015, Estonia v Parliament and Council (C‑508/13, EU:C:2015:403, paragraph 53). See also, for example, judgment of 4 May 2016, Poland v Parliament and Council (C‑358/14, EU:C:2016:323, paragraph 119). 69      Judgment of 18 June 2015, Estonia v Parliament and Council (C‑508/13, EU:C:2015:403, paragraph 54). 70      See, in that respect, Wyatt, D., ‘Could a “yellow card” for national parliaments strengthen judicial as well as political policing of subsidiarity?’, Croatian Yearbook of European Law & Policy, Vol. 2, 2006, p. 1, in particular p. 10. 71      In her Opinion in Poland v Parliament and Council (C‑358/14, EU:C:2015:848, points 146 and 147), Advocate General Kokott similarly considered that the Court can exercise only limited judicial review; the Court can reasonably review only whether the EU institutions have kept within the limits of their discretion in exercising their competences, looking for manifest errors on their part. 72      Craig, P. and De Búrca G., EU Law: Text, Cases and Materials, 8th edition, Oxford University Press, Oxford, 2024, p. 130. 73      As also suggested in the Opinion of Advocate General Poiares Maduro in Vodafone and Others (C‑58/08, EU:C:2009:596, point 30). 74      In that respect, see Opinion of Advocate General Kokott in Poland v Parliament and Council (C‑358/14, EU:C:2015:848, points 177 to 188), noting that, in those proceedings, despite the use of a standard formula, documentary evidence was sufficient, but advising the EU institutions to avoid generic formulas and to enhance the preamble with sufficiently substantial statements regarding the principle of subsidiarity tailored to the measure in question. 75      See, in that respect, Öberg, J., ‘Subsidiarity as a Limit to the Exercise of EU Competences’, Yearbook of European Law, Vol. 36, No 1, 2017, p. 391. 76      Commission proposal for a Regulation of the European Parliament and of the Council on asylum and migration management and amending Council Directive (EC) 2003/109 and the proposed Regulation (EU) XXX/XXX [Asylum and Migration Fund], COM(2020) 610 final, 23 September 2020 (‘Proposal’). See also, in that regard, Opinion of the European Committee of the Regions (OJ 2021 C 175, p. 32), point 26, as well as Opinion of the European Economic and Social Committee (OJ 2021 C 155, p. 58), point 1.1. 77      Proposal, cited in footnote 76 of the present Opinion, Explanatory Memorandum, section 2.4. 78      Proposal, cited in footnote 76 of the present Opinion, Explanatory Memorandum, section 1.1. (emphasis added). 79      European Parliamentary Research Service, The European Commission’s New Pact on Asylum and Migration. Horizontal substitute impact assessment, PE 694.210  August 2021 (‘Parliament impact assessment’), section 4.3., in particular sub-section 4.3.2. 80      Parliament impact assessment, cited in point 79 of the present Opinion, p. 50. 81      European Parliament Resolution of 9 October 1986 on an initiative concerning negotiations within the Council on the drawing up of a common European policy on refugees (OJ 1986 C 283, p. 74), point 3. 82      Commission Communication to the Council and the European Parliament on immigration, SEC(91) 1855 final, 23 October 1991, pp. 2 and 8. 83      Communication from the Commission to the Council and the European Parliament on immigration and asylum policies, COM(94) 23 final, 23 February 1994, p. 1. 84      Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions on enhanced intra-EU solidarity in the field of asylum  An EU agenda for better responsibility-sharing and more mutual trust, COM(2011) 835 final, 2 December 2011, p. 1. 85      Communication from the Commission to the European Parliament and the Council  European Asylum and Migration Management Strategy, COM(2026) 45 final, 29 January 2026, p. 12 (emphasis added).