C-767/24

Provisional text JUDGMENT OF THE COURT (Ninth Chamber) 11 December 2025 (*) ( Reference for a preliminary ruling – Consumer protection – Directive 93/13/EEC – Unfair terms in consumer contracts – Article 7(1) – Effects of a term being found to be unfair – Contract declared void – Action brought by a seller or supplier seeking restitution of the amount of the loan paid under a contract which is to be annulled – Consequences of the submission of a declaration of set-off – Implied waiver of the objection that the action is time-barred – Effective exercise of the procedural rights of consumers – Principle of effectiveness – Dissuasive effect of the prohibition on unfair terms ) In Case C‑767/24 [Kuszycka], (i) REQUEST for a preliminary ruling under Article 267 TFEU from the Sąd Okręgowy w Warszawie (Regional Court, Warsaw, Poland), made by decision of 6 November 2024, received at the Court on 6 November 2024, in the proceedings mBank S.A. v ML, THE COURT (Ninth Chamber), composed of M. Condinanzi, President of the Chamber, N. Jääskinen and R. Frendo (Rapporteur), Judges, Advocate General: R. Norkus, Registrar: A. Calot Escobar, having regard to the written procedure, after considering the observations submitted on behalf of: –        mBank S.A., by A. Cudna-Wagner, radca prawny, and B. Miąskiewicz, adwokat, –        ML, by I. Gabrysiak, adwokat, –        the Polish Government, by B. Majczyna, acting as Agent, –        the European Commission, by P. Kienapfel and J. Szczodrowski, acting as Agents, having decided, after hearing the Advocate General, to proceed to judgment without an Opinion, gives the following Judgment 1        This request for a preliminary ruling concerns the interpretation of Article 7(1) of Council Directive 93/13/EEC of 5 April 1993 on unfair terms in consumer contracts (OJ 1993 L 95, p. 29) and of the principle of effectiveness. 2        The request has been made in proceedings between mBank S.A., a banking institution, and ML, a consumer, concerning an action seeking restitution in respect of a debt resulting from the use of a sum of money lent under a mortgage loan agreement, which had to be annulled on the ground that it contains unfair terms.  Legal framework  European Union law 3        The twenty-fourth recital of Directive 93/13 states that ‘the courts or administrative authorities of the Member States must have at their disposal adequate and effective means of preventing the continued application of unfair terms in consumer contracts’. 4        Article 6(1) of that directive provides: ‘Member States shall lay down that unfair terms used in a contract concluded with a consumer by a seller or supplier shall, as provided for under their national law, not be binding on the consumer and that the contract shall continue to bind the parties upon those terms if it is capable of continuing in existence without the unfair terms.’ 5        Article 7(1) of that directive provides: ‘Member States shall ensure that, in the interests of consumers and of competitors, adequate and effective means exist to prevent the continued use of unfair terms in contracts concluded with consumers by sellers or suppliers.’  Polish law 6        Under Article 58(1) of the ustawa – Kodeks cywilny (Law establishing the Civil Code), of 23 April 1964 (Dz. U No 16, item 93), in the version applicable to the dispute in the main proceedings (‘the Civil Code’): ‘A legal transaction which is contrary to the law or intended to circumvent the law shall be null and void, unless the relevant provision provides otherwise, in particular that the invalid terms of the legal transaction are to be substituted by relevant provisions of law.’ 7        Article 117 of the Civil Code provides: ‘1.      Subject to the exceptions provided for by law, property-related claims shall be subject to limitation. 2.      Following the expiry of the limitation period, a person against whom a claim may be pursued may avoid the duty to satisfy it, unless he or she waives his or her right to use the defence of limitation. However, waiving the defence of limitation before the expiry of the limitation period shall be invalid. 21      Once the limitation period has expired, it shall no longer possible to pursue a claim against a consumer.’ 8        Article 118 of that code provides: ‘Unless a specific provision provides otherwise, the limitation period shall be six years, and for claims concerning periodic payments, as well as claims related to the pursuit of a business activity, it shall be three years. However, the end of the limitation period shall be the last day of the calendar year unless the limitation period is shorter than two years.’ 9        Article 123(1) of that code is worded as follows: ‘The limitation period shall be interrupted: (1) by any act before a court of law or other authority appointed to try cases or to enforce claims of a given kind or before an arbitration court, which activity is taken up directly to pursue or to establish or to satisfy or to secure a claim; (2) by the acknowledgement of a claim by a person against whom the claim may be pursued; (3) by initiating mediation.’ 10      Under Article 3851(1) and (2) of that code: ‘1.      The terms of a contract concluded with a consumer which have not been individually negotiated shall not be binding on the consumer if his or her rights and obligations are set forth in a way that is contra bonos mores and grossly infringes his or her interests (unlawful contractual terms). This provision shall not apply to terms setting out the principal obligations to be performed by the parties, including price or remuneration, so long as they are worded clearly. 2.      If a contractual term is not binding on the consumer pursuant to paragraph 1, the contract shall otherwise continue to be binding on the parties.’ 11      Under Article 405 of the Civil Code: ‘Any person who, without legal grounds, has obtained an economic advantage at the expense of another person shall be required to restore that advantage in kind and, where that is not possible, to return the value thereof.’ 12      Article 410(1) and (2) of that code provides: ‘1.      The provisions of the preceding articles shall apply in particular to undue performance. 2.      A performance shall be undue if the person who rendered it was not under an obligation to render it or was not under an obligation to render it to the person to whom it was rendered, if the basis for the performance has ceased to exist, if the objective of the performance has not been achieved or if the transaction on which the obligation to render the performance was based was void and has not become valid since the performance was rendered.’ 13      Article 498(1) and (2) of that code provides: ‘1.      If two persons are simultaneously debtors and creditors with respect to each other, each of them may set off their claim against the claim of the other party, if the object of both claims is money or generic goods of the same quality, and both claims are due and can be enforced before a court or other State body. 2.      As a result of set-off, the two claims are offset against each other to the extent of the lower claim.’ 14      Article 499 of that code reads as follows: ‘A set-off shall be effected by a declaration submitted to the other party. The declaration shall have retroactive effect from the moment when the set-off became possible.’  The dispute in the main proceedings and the question referred for a preliminary ruling 15      On 11 October 2006, ML concluded a mortgage loan agreement with mBank for 130 000 Polish zlotys (PLN) (approximately EUR 30 670), with a view to purchasing immovable property. That agreement, concluded for a period of 360 months, was denominated in Swiss francs (CHF), but provided for reimbursement of the monthly instalments in Polish zlotys, the amount of which was determined by applying the selling rate for the Swiss franc published in mBank’s table of exchange rates on the payment date of those monthly instalments. 16      On 12 October 2017, ML sent mBank a request for a summons to a conciliatory settlement, seeking reimbursement of the sums of PLN 53 244.39 (approximately EUR 12 530) and CHF 14 692.51 (approximately EUR 15 700), which she considered herself to have wrongfully paid on account of the presence of unfair terms in that agreement. 17      On 16 December 2021, mBank brought an action before the Sąd Okręgowy w Warszawie (Regional Court, Warsaw, Poland), which is the referring court, seeking that ML be ordered to reimburse the loan capital, that is to say, an amount of PLN 130 000 (approximately EUR 30 670), plus default interest at the statutory rate. The banking institution submitted that, since the mortgage loan agreement was void, ML is required to reimburse the loan capital, pursuant to the provisions of national law on unjust enrichment. 18      In her statement in defence, ML contended that the action should be dismissed and entered an objection that the claim was time-barred. The above notwithstanding, she submitted a declaration of set-off, relying on claims amounting to PLN 53 244.39 (approximately EUR 12 530) and CHF 14 692.51 (approximately EUR 15 700). 19      The referring court notes that the agreement at issue in the main proceedings contains unfair terms and that it is not capable of continuing in existence without those terms. That means that the loan agreement must be declared void and that, pursuant to the national law, the parties are required to restore to each other the payments made under that agreement. 20      Moreover, that court observes that, in accordance with Article 118 of the Civil Code, the limitation period of three years applicable to the banking institution’s claim expired on 31 December 2020. Therefore, at the date when the action in the main proceedings was brought, namely 16 December 2021, that institution’s claim would have been time-barred. Consequently, in the light of the objection that the claim was time-barred raised by ML, that court would be required to dismiss the action. 21      However, that court points out that, according to national case-law, the submission of a declaration of set-off, in accordance with Article 499 of the Civil Code, implies a waiver of the objection that the opposing party’s action is time-barred, under Article 117(2) of that code. It follows from that case-law that a party which submits a declaration of set-off therefore acknowledges the existence of the opposing claim and expresses the intention to satisfy that claim, thus waiving the possibility of relying on limitation. Such an approach, which is also accepted in Polish academic legal literature, would lead the national courts to find that the submission of a declaration of set-off, even by way of a defence, is equivalent to waiving an objection that the action is time-barred. It follows that, in accordance with that case-law, ML’s objection that the banking institution’s claim is time-barred cannot be accepted and that institution’s claim cannot be regarded as time-barred. 22      The national court has doubts as to the compatibility of such national case-law with Article 7(1) of Directive 93/13. 23      In that regard, that court states that ML could have submitted a declaration of set-off with the sole intention of countering the banking institution’s claim with her own claim, without having the intention of waiving the objection that the banking institution’s claim was time-barred, a fortiori since she raised those two pleas at the same time. Moreover, in so far as ML did not expressly waive the objection that the banking institution’s claim was time-barred, it cannot be ruled out that ML was not aware of the fact that the declaration of set-off could be interpreted in that way. 24      According to that court, national case-law according to which the declaration of set-off automatically entails a waiver of the objection that a claim is time-barred may prove to be contrary to the objectives of consumer protection pursued by Directive 93/13. Such case-law is liable to deter consumers from having recourse to the set-off mechanism, even though that mechanism is an effective means of asserting their rights in the case of unfair terms. Furthermore, both the principle of consumer protection and the principle of legal certainty support an interpretation of national law according to which the admission of a time-barred action brought by a seller or supplier against a consumer can be envisaged only in exceptional and clearly defined circumstances. 25      However, that court observes that, if ML’s objective, in lodging a declaration of set-off, were to extinguish mBank’s claim, the submission of such a declaration could be regarded as implying acknowledgment of the existence of that claim, in the absence of which set-off would be devoid of purpose. Furthermore, ML is represented by a lawyer who, in the light of his function, should know the national case-law, according to which the lodging of a declaration of set-off constitutes a waiver of the objection that a claim is time-barred. 26      In those circumstances, the Sąd Okręgowy w Warszawie (Regional Court, Warsaw) decided to stay the proceedings and to refer the following question to the Court of Justice for a preliminary ruling: ‘Must Article 7(1) of Council Directive [93/13] and the principle of effectiveness be interpreted as precluding a judicial interpretation of national provisions according to which, in the context of the [annulment] of a mortgage loan agreement in its entirety because it is not capable of continuing in existence without the unfair terms, the [submission], by the consumer, of a declaration that he or she wishes to set off his or her claim against the bank’s claim for repayment of the loan capital is equivalent to the consumer’s waiving his or her objection that the bank’s claim is time-barred?’  Consideration of the question referred  Admissibility 27      Both parties to the main proceedings dispute the admissibility of the question referred for a preliminary ruling. 28      In the first place, mBank submits that the request for a preliminary ruling does not satisfy the requirements of Article 94 of the Rules of Procedure of the Court of Justice. In particular, it claims that the referring court did not provide any information on the circumstances in which ML submitted her declaration of set-off or on the content of that declaration. 29      Under Article 94 of the Rules of Procedure, any request for a preliminary ruling is to contain ‘a summary of the subject matter of the dispute and the relevant findings of fact as determined by the referring court or tribunal, or, at least, an account of the facts on which the questions are based’, ‘the tenor of any national provisions applicable in the case and, where appropriate, the relevant national case-law’ and ‘a statement of the reasons which prompted the referring court or tribunal to inquire about the interpretation or validity of certain provisions of European Union law, and the relationship between those provisions and the national legislation applicable to the main proceedings’. 30      In the present case, the request for a preliminary ruling contains a description of the factual and legal context of the dispute in the main proceedings sufficient to satisfy those requirements. First, that request reproduces the tenor of the national provisions applicable to the dispute in the main proceedings and of the relevant national case-law. Second, the referring court’s description of the circumstances in which ML submitted her declaration of set-off, and of the questions which that court expresses as to the legal consequences attached to such a declaration by national case-law, is sufficient to understand the reasons underlying the choice of the provisions of EU law of which that court seeks an interpretation and the link it establishes between those provisions and the national legislation applicable to the dispute before it. 31      In the second place, mBank and ML submit that the question referred for a preliminary ruling is hypothetical, on the ground that ML lodged her declaration of set-off only in the alternative and subsequently withdrew it by document of 4 November 2024. The question relating to set-off and the effects attached to that declaration is therefore irrelevant to the resolution of the dispute in the main proceedings. 32      In that regard, it should be noted that, following a request for information sent to it by the Court, the referring court confirmed that ML had withdrawn her declaration of set-off. However, that court stated that it wished to maintain its request for a preliminary ruling, on the ground that an answer to the question referred is still necessary for it to resolve the dispute in the main proceedings. That court stated, in that regard, that the Polish legislation allows the withdrawal of the plea of set-off, understood as a procedural plea, but does not authorise the withdrawal of a declaration of set-off, understood as a declaration going to the substance of the case. It added that, in any event, the initial declaration of set-off amounts to acknowledgment of a debt, which, under Article 123 of the Civil Code, interrupts the limitation period. Therefore, that period starts to run again from the date of that implied acknowledgment, without the subsequent withdrawal of the declaration being capable of having retroactive effect and nullifying that implied acknowledgment. 33      It is important to note that, in the context of the cooperation between the Court and the national courts provided for in Article 267 TFEU, it is solely for the national court before which a dispute has been brought, and which must assume responsibility for the subsequent judicial decision, to determine in the light of the particular circumstances of the case both the need for a preliminary ruling in order to enable it to deliver judgment and the relevance of the questions which it submits to the Court. Consequently, where the questions submitted concern the interpretation of EU law, the Court is, in principle, bound to give a ruling (see judgments of 29 November 1978, Redmond, 83/78, EU:C:1978:214, paragraph 25, and of 11 January 2024, Nárokuj, C‑755/22, EU:C:2024:10, paragraph 17 and the case-law cited). 34      It follows that questions relating to EU law enjoy a presumption of relevance. The Court may refuse to rule on a question referred for a preliminary ruling by a national court only where it is quite obvious that the interpretation of EU law that is sought bears no relation to the actual facts of the main action or its purpose, where the problem is hypothetical, or where the Court does not have before it the factual or legal material necessary to give a useful answer to the questions submitted to it (see judgments of 7 September 1999, Beck and Bergdorf, C‑355/97, EU:C:1999:391, paragraph 22, and of 11 January 2024, Nárokuj, C‑755/22, EU:C:2024:10, paragraph 18 and the case-law cited). 35      In the present case, first, it is apparent from the response to the request for information, referred to in paragraph 32 above, provided by the referring court, which alone has jurisdiction to interpret the national law, that the declaration of set-off is equivalent, under Polish law, to acknowledgment of a debt, producing legal effects irrespective of whether it is withdrawn, which, moreover, is not permitted under the applicable national law. 36      Second, the dispute in the main proceedings concerns an action for restitution brought by a banking institution in order to obtain repayment of the capital lent under a mortgage loan agreement containing unfair terms and which must be annulled. The referring court is uncertain as to the compatibility with Article 7(1) of Directive 93/13, read in the light of the principle of effectiveness, of national case-law according to which the submission by a consumer of a declaration of set-off of his or her claim against that of the banking institution entails an implied waiver of the objection that the banking institution’s claim is time-barred. 37      In those circumstances, it is not obvious that the interpretation of Directive 93/13 that is sought bears no relation to the actual facts of the main proceedings or its purpose or that the problem raised is hypothetical. 38      In the third and last place, mBank submits that the provisions of Directive 93/13 are not applicable to the effects of a declaration of set-off made in the context of an action for restitution, with the result that that question is governed solely by national law. 39      It is sufficient to note in that regard that, where, as in the present case, it is not obvious that the interpretation of an act of EU law bears no relation to the actual facts of the main action or its purpose, the objection alleging that that act is inapplicable to the case in the main proceedings goes to the substance of the questions (judgment of 15 June 2023, Getin Noble Bank (Suspension of the performance of a loan agreement), C‑287/22, EU:C:2023:491, paragraph 27 and the case-law cited). 40      It follows from all the foregoing considerations that the question referred is admissible.  Substance 41      By its single question, the referring court asks, in essence, whether Article 7(1) of Directive 93/13, read in the light of the principle of effectiveness, must be interpreted as meaning that, in the context of the annulment in its entirety of a mortgage loan agreement concluded between a consumer and a banking institution, on the ground that that agreement contains an unfair term without which that agreement cannot continue in existence, it precludes the application of national case-law according to which the submission by that consumer of a declaration of set-off of his or her claim against that of that banking institution entails an implied waiver of the objection that the claim relied on by that institution is time-barred. 42      It must be borne in mind that the system of protection introduced by Directive 93/13 is based on the idea that the consumer is in a weak position vis-à-vis the seller or supplier, as regards both his or her bargaining power and his or her level of knowledge. This leads to the consumer agreeing to terms drawn up in advance by the seller or supplier without being able to influence the content of those terms (judgment of 15 June 2023, Bank M. (Consequences of the annulment of the contract), C‑520/21, EU:C:2023:478, paragraph 54 and the case-law cited). 43      It is therefore the case that, given the nature and significance of the public interest constituted by the protection of consumers, Directive 93/13 and, in particular, Article 7(1) thereof, read in conjunction with its 24th recital, obliges the Member States to provide for adequate and effective means to prevent the continued use of unfair terms in contracts concluded with consumers by sellers or suppliers. To do this, it is for the national courts to exclude the application of the unfair terms so that they do not produce binding effects with regard to the consumer concerned, unless the consumer objects (judgment of 15 June 2023, Bank M. (Consequences of the annulment of the contract), C‑520/21, EU:C:2023:478, paragraph 56 and the case-law cited). 44      While the Court has already defined, on several occasions, the way in which the national court must ensure that the rights which consumers derive from Directive 93/13 are protected, the fact remains that, in principle, EU law does not harmonise the procedures applicable to examining whether a contractual term is unfair or the consequences to be drawn from a finding that such a term is unfair. Thus, in the absence of specific EU rules governing the matter, the means of the implementation of the consumer protection provided for by that directive are governed by the internal legal order of the Member States by virtue of the principle of procedural autonomy of those States. Nevertheless, those means of implementation must not be less favourable than those governing similar domestic actions (principle of equivalence) and may not be framed in such a way as to make it in practice impossible or excessively difficult to exercise the rights conferred by the EU legal order (principle of effectiveness) (see, to that effect, judgments of 25 November 2020, Banca B., C‑269/19, EU:C:2020:954, paragraph 39, and of 26 June 2019, Addiko Bank, C‑407/18, EU:C:2019:537, paragraphs 45 and 46 and the case-law cited). 45      As regards the principle of effectiveness, which is the only principle concerned by the issues raised by the referring court, it should be noted that every case in which the question arises as to whether a national procedural provision makes the application of EU law impossible or excessively difficult must be analysed by reference to the role of that provision in the procedure, its progress and its special features, viewed as a whole, before the various national bodies. In that context, it is necessary to take into consideration, where relevant, the principles which lie at the basis of the national legal system, such as the protection of the rights of the defence, the principle of legal certainty and the proper conduct of the proceedings (judgment of 26 June 2019, Addiko Bank, C‑407/18, EU:C:2019:537, paragraph 48 and the case-law cited). 46      In addition, the Court has stated that the obligation on the Member States to ensure the effectiveness of the rights that individuals derive from EU law, particularly the rights deriving from Directive 93/13, implies a requirement for effective judicial protection, also guaranteed by Article 47 of the Charter of Fundamental Rights of the European Union, which applies, inter alia, to the definition of detailed procedural rules relating to actions based on such rights (judgment of 10 June 2021, BNP Paribas Personal Finance, C‑776/19 to C‑782/19, EU:C:2021:470, paragraph 29 and the case-law cited). 47      The adequate and effective means that are to guarantee the consumer a right to an effective remedy must include the possibility of taking part in an action brought against him or her by a seller or supplier, under reasonable procedural conditions, so that the exercise of his or her rights is not subject to conditions, in particular time limits, costs or other procedural requirements, which make it excessively difficult or impossible in practice to exercise the rights guaranteed by Directive 93/13 (see, to that effect, judgments of 1 October 2015, ERSTE Bank Hungary, C‑32/14, EU:C:2015:637, paragraph 59, and of 3 April 2019, Aqua Med, C‑266/18, EU:C:2019:282, paragraph 53 and the case-law cited). 48      In the present case, it is apparent from the order for reference that, in the context of an action for restitution brought by mBank in order to recover a debt arising from a mortgage loan agreement which must be annulled on the ground that it contains unfair terms, ML raised an objection that that claim was time-barred and simultaneously submitted a declaration of set-off in order to offset her own claim against that of the banking institution. 49      It is also apparent that, on the date on which the action in the main proceedings was brought, the banking institution’s claim was time-barred, with the result that, in view of the objection to that effect raised by ML, the referring court would be required to dismiss the action. However, that court notes that, according to national case-law, the submission of a declaration of set-off, in accordance with Article 499 of the Civil Code, entails waiver of the objection that a claim is time-barred, within the meaning of Article 117(2) of that code, with the result that the objection raised by ML cannot be accepted and that the bank’s claim cannot be regarded as time-barred. 50      In that regard, it should be noted, in the first place, that making entitlement to rely on the objection that a claim is time-barred subject to abstaining from any declaration of set-off amounts, in reality, to restricting the possibility for the consumer to exercise a procedural right provided for by the national legislation, namely the right to assert a reciprocal claim arising from the annulment of the loan agreement at issue. Such a limitation may, in the context of an action brought by the seller or supplier against the consumer, constitute a barrier liable to prevent or deter the consumer from effectively exercising his or her procedural rights, contrary to the case-law cited in paragraphs 46 and 47 above. 51      In the second place, it is apparent that the national case-law at issue in the main proceedings is also liable to call into question the dissuasive effect that Article 6(1) of Directive 93/13, read in conjunction with Article 7(1) of that directive, is designed to attach to a finding of unfairness in respect of terms in contracts concluded between consumers and sellers or suppliers (see, by analogy, judgment of 14 December 2023, Getin Noble Bank (Limitation period for actions for restitution), C‑28/22, EU:C:2023:992, paragraph 74 and the case-law cited). 52      As is apparent from the information set out by the referring court and recalled in paragraph 49 above, that national case-law appears to be such as to lead to a seller or supplier being able to recover a debt which is time-barred solely on the ground that the consumer, while raising an objection that that claim was time-barred, has exercised a procedural means granted to him or her under national law, namely the submission of a declaration of set-off. That case-law is thus liable to render ineffective the mechanism established by Directive 93/13 for the purposes of preventing the use of unfair terms in contractual relations between sellers or suppliers and consumers, since it has the effect of neutralising the legal effects of the annulment of the contract at issue and of allowing the seller or supplier to derive an advantage from his or her own unlawful conduct, which gave rise to that annulment. 53      In the third and last place, it should be borne in mind that the system of protection of the consumer against unfair terms and against the unfavourable consequences of the annulment of the contract in its entirety, implemented by Directive 93/13, is not applicable if the consumer objects to it. The latter is entitled, after having been informed by the national court, not to assert the unfair and non-binding nature of a term, thus giving free and informed consent to the term in question and thereby preventing the contract from being invalidated. In order for the consumer to be able to give free and informed consent, it is for the national court to indicate to the parties, in the context of national procedural rules and in the light of the principle of equity in civil proceedings, objectively and exhaustively the legal consequences which the removal of the unfair term may entail, irrespective of whether or not they are represented by a professional representative (see, to that effect, judgment of 29 April 2021, Bank BPH, C‑19/20, EU:C:2021:341, paragraphs 94, 95 and 97). 54      Similarly, a waiver of the objection that a claim is time-barred cannot be presumed solely on the basis of national case-law which regards a procedural act, such as a declaration of set off, as an implied expression of intention to waive that objection, without it being verified that the consumer has expressed a free and informed intention to do so. The same interpretation applies, a fortiori, in a situation such as that at issue in the main proceedings, where the consumer has, by another procedural act submitted at the same time, expressly expressed the contrary intention to rely on the defence of limitation. 55      As the Polish Government stated, in essence, in its written observations, Article 7(1) of Directive 93/13 and the principle of effectiveness require that the consumer be able effectively to assert the rights conferred on him or her by that directive, without the exercise of a particular procedural right being automatically treated as an implied waiver of another right. It must therefore be held that national case-law which infers an implied waiver of the objection that a claim is time-barred from the mere submission of a declaration of set-off, without verifying the consumer’s intention, fails to comply with that requirement. 56      That assessment cannot be invalidated by the fact that ML was represented by a lawyer who, in the light of his function, ought to be aware of the national case-law at issue, such a circumstance, in principle, not affecting the protection conferred on consumers by Directive 93/13 (see, by analogy, judgment of 11 March 2020, Lintner, C‑511/17, EU:C:2020:188, paragraph 40 and the case-law cited). 57      It must also be borne in mind that the principle that national law must be interpreted in conformity with EU law requires national courts to do whatever lies within their jurisdiction, taking the whole body of domestic law into consideration and applying the interpretative methods recognised by it, with a view to ensuring that the directive in question is fully effective and achieving an outcome consistent with the objective pursued by it. The requirement of such an interpretation entails, in particular, the obligation for national courts to change established case-law, where necessary, if it is based on an interpretation of national law that is incompatible with the objectives of a directive. Consequently, a national court cannot validly claim that it is impossible for it to interpret a provision of national law in a manner that is consistent with EU law merely because that provision has consistently been interpreted in a manner that is incompatible with EU law (judgment of 26 June 2019, Addiko Bank, C‑407/18, EU:C:2019:537, paragraphs 65 and 66 and the case-law cited). 58      In the present case, it is for the referring court to satisfy itself that the provisions of national law cannot be interpreted in such a way as to prevent or deter the consumer, on the sole ground that that consumer has submitted a declaration of set-off, from being able effectively to rely on the objection that the claim relied on by the banking institution is time-barred. 59      Accordingly, it is for that court to disapply, if necessary, of its own motion, the national case-law at issue in the main proceedings, since that case-law does not appear to be compatible with Article 7(1) of Directive 93/13. 60      In the light of the foregoing considerations, the answer to the question raised is that Article 7(1) of Directive 93/13, read in the light of the principle of effectiveness, must be interpreted as meaning that, in the context of the annulment in its entirety of a mortgage loan agreement concluded between a consumer and a banking institution, on the ground that that agreement contains an unfair term without which that agreement cannot continue in existence, it precludes the application of national case-law according to which the submission by that consumer of a declaration of set-off of his or her claim against that of that banking institution entails an implied waiver of the objection that the claim relied on by that institution is time-barred.  Costs 61      Since these proceedings are, for the parties to the main proceedings, a step in the action pending before the referring court, the decision on costs is a matter for that court. Costs incurred in submitting observations to the Court, other than the costs of those parties, are not recoverable. On those grounds, the Court (Ninth Chamber) hereby rules: Article 7(1) of Council Directive 93/13/EEC of 5 April 1993 on unfair terms in consumer contracts, read in the light of the principle of effectiveness, must be interpreted as meaning that, in the context of the annulment in its entirety of a mortgage loan agreement concluded between a consumer and a banking institution, on the ground that that agreement contains an unfair term without which that agreement cannot continue in existence, it precludes the application of national case-law according to which the submission by that consumer of a declaration of set-off of his or her claim against that of that banking institution entails an implied waiver of the objection that the claim relied on by that institution is time-barred. [Signatures] *      Language of the case: Polish. i      The name of the present case is a fictitious name. It does not correspond to the real name of any party to the proceedings.