1) This request for a preliminary ruling concerns the interpretation of Article 169 TFEU, Articles 20, 21, 38 and 47 of the Charter of Fundamental Rights of the European Union (‘the Charter’), Article 7(1) and (2) of Council Directive 93/13/EEC of 5 April 1993 on unfair terms in consumer contracts (OJ 1993 L 95, p. 29), read in the light of Article 8 of that directive and of recital 47 of Directive 2008/48/EC of the European Parliament and of the Council of 23 April 2008 on credit agreements for consumers and repealing Council Directive 87/102/EEC (OJ 2008 L 133, p. 66, and corrigenda OJ 2009 L 207, p. 14; OJ 2010 L 199, p. 40, and OJ 2011 L 234, p. 46).

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27) In those circumstances, the Fővárosi Törvényszék (Budapest High Court) decided to stay the proceedings and to refer the following questions to the Court for a preliminary ruling:

‘(1) Must the following provisions of EU law, namely, Article 169(1) and (2) [TFEU], read in the light of Article 169(3) thereof; Article 38 of the [Charter]; Article 7(1) and (2) of [Directive 93/13], read in the light of Article 8 of that directive, and recital 47 of [Directive 2008/48], be interpreted as precluding rules of national law (and their application) that impose additional requirements prejudicial to a party to proceedings, whether applicant or defendant, who, in the period from 1 May 2004 to 26 July 2014, has, in the capacity of a consumer, entered into a credit agreement containing an unfair contractual term allowing [an option of unilateral amendment] or an unfair contractual term relating to [a difference in exchange rates], where those additional requirements stipulate, inter alia, in order that the rights arising from the invalidity of those agreements concluded with consumers may effectively be upheld before the courts and in order that the court may be able to examine the substance of a case, a civil procedural document must be presented (primarily a claim, amendment of a claim or a plea of invalidity relied on by way of defence contesting the order against the consumer, amendment of that plea, a counterclaim by the defendant or amendment of that counterclaim) with certain mandatory content, whereas a party to the proceedings who has not entered into a credit agreement or who, in that period, has, in the capacity of a consumer, entered into a credit agreement of a different kind from that described above, does not have to present such a document satisfying certain mandatory requirements as to content?

(2) Irrespective of whether the Court answers [the first question], which is formulated in more general terms than this question, in the affirmative or the negative, must the provisions of EU law listed [in the first question] be interpreted as precluding the following obligatory additional requirements [(a) to (c)] from applying to a party to proceedings who has, in the capacity of a consumer, entered into a credit agreement, as referred to [in the first question]:

(a) in judicial proceedings, a claim, an amendment of a claim or a plea of invalidity relied upon by way of defence contesting the order against the consumer, amendment of that plea, a counterclaim by the defendant or an amendment of that counterclaim which must be presented by a party to proceedings, whether applicant or defendant, that has entered into a credit agreement, in the capacity of a consumer, as referred to [in the first question], will be admissible, that is to say, will be examined as to its substance, only if, in that document, the party not only requests the court to declare invalid in whole or in part the consumer credit agreement referred to [in the first question], but also requests the court to apply the legal consequences associated with total invalidity, whereas another party to proceedings who has not, in the capacity of a consumer, entered into a credit agreement or who, in that period, has, in the capacity of a consumer, entered into a credit agreement of a different kind from that described above, does not have to present such a document satisfying certain mandatory requirements as to content?

(b) in judicial proceedings, a claim, an amendment of a claim or a plea of invalidity relied upon by way of defence contesting the order against the consumer, amendment of that plea, a counterclaim by the defendant or amendment of that counterclaim that must be presented by a party to proceedings, whether applicant or defendant, who in the capacity of a consumer has entered into a credit agreement, as referred to [in the first question], will be admissible, that is to say, will be examined as to its substance, only if, in that document, the applicant does not, in addition to seeking a declaration that the credit agreement entered into as a consumer, as referred to [in the first question], is wholly invalid, request the court to apply, among the legal consequences associated with total invalidity, that of judicially restoring the situation as it stood before the credit agreement was concluded, whereas another party to proceedings who has not, in the capacity of a consumer, entered into a credit agreement or who, in that period, has, in the capacity of a consumer, entered into a credit agreement of a different kind from that described above, does not have to present such a document satisfying certain mandatory requirements as to content?

(c) in judicial proceedings, a claim, amendment of a claim or a plea of invalidity relied upon by way of defence contesting the order against the consumer, amendment of that plea, a counterclaim by the defendant or amendment of that counterclaim that must be presented by a party to proceedings, whether applicant or defendant, who has, in the capacity of a consumer, entered into a credit agreement, as referred to [in the first question], will be admissible, that is to say, will be examined as to its substance, only if that document includes, for the period from the beginning of the contractual legal relationship to the date the application is lodged, a settlement calculation, extremely complex from a mathematical point of view (as prescribed by national provisions), that must be made also taking into account the rules regulating currency conversion into HUF, and that settlement calculation must include a detailed breakdown, arithmetically verifiable, indicating the payments due under the credit agreement, payments made by the applicant, the payments due leaving aside the void clause, and the difference between those figures; and specifying the grand total that the party who, in the capacity of a consumer, entered into the credit agreement, as referred to [in the first question], still owes to the credit institution or paid in excess, whereas another party to proceedings who has not, in the capacity of a consumer, entered into a credit agreement or who, in that period, has, in the capacity of a consumer, entered into a credit agreement of a different kind from that described above, does not have to present such a document satisfying certain mandatory requirements as to content?

(3) Must the provisions of EU law listed [in the first question] be interpreted as meaning that infringement of those provisions by means of the imposition of the additional requirements referred to [in the first and second questions]

at the same time constitutes an infringement of Articles 20, 21 and 47 of the Charter …,

taking into account likewise … that the courts of the Member States must apply EU law in the field of consumer protection even in cases without any cross-border elements, that is to say, in purely internal situations, in accordance with the judgments of 5 December 2000, Guimont, C‑448/98, EU:C:2000:663, paragraph 23, and of 10 May 2012, Duomo Gpa and Others, C‑357/10 to C‑359/10, EU:C:2012:283, paragraph 28, and the order of 3 July 2014, Tudoran, C‑92/14, EU:C:2014:2051, paragraph 39, or must the present situation be regarded as a cross-border situation merely because the credit agreements referred to [in the first question] are “foreign currency-based credit agreements”?’

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29) Directive 93/13, however, is directed against unfair terms in consumer contracts. It is therefore appropriate, having regard to the subject matter of the dispute in the main proceedings, to interpret that directive, read in the light of the relevant provisions of the Charter, in particular Article 47 thereof, which enshrines the right to effective judicial protection.

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35) While the Court has thus previously circumscribed, in a number of respects and taking account of the requirements set out in Article 6(1) and Article 7(1) of Directive 93/13, the manner in which national courts must guarantee the protection of rights which consumers derive from that directive, the fact remains that, in principle, EU law does not harmonise the procedures which apply for the assessment of an allegedly unfair contractual term, and that those procedures are therefore a matter for the national legal order, provided that they are not less favourable than those governing similar situations subject to domestic law (principle of equivalence) and that they afford effective judicial protection, as provided for in Article 47 of the Charter (see, to that effect, judgment of 14 April 2016, Sales Sinués and Drame Ba, C‑381/14 and C‑385/14, EU:C:2016:252, paragraph 32 and the case-law cited).

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49) As regards, second, the principle of effective judicial protection, it must be pointed out that the obligation of Member States to lay down detailed procedural rules to ensure respect for the rights which individuals derive from Directive 93/13 against the use of unfair terms implies a requirement for effective judicial protection, also guaranteed by Article 47 of the Charter. That protection must be assured both as regards the designation of courts having jurisdiction to hear and determine actions based on EU law and as regards the definition of detailed procedural rules relating to such actions (see, to that effect, judgment of 17 July 2014, Sánchez Morcillo and Abril García, C‑169/14, EU:C:2014:2099, paragraph 35 and the case-law cited).