37) The applicants rely on exceptional circumstances and claim, in essence, that, in the light of the extremely late adoption of the requisition measures, they are entitled to seek annulment of the decisions adopted after the action was brought. They add that, while it is true that those decisions had not been adopted at the date on which the action was brought, it was nevertheless certain that they would be adopted. According to the applicants, requiring them to bring before the Court as many actions as there are decisions adopted would be manifestly disproportionate, unreasonable and incompatible with the sound administration of justice, and would infringe the right to an effective remedy provided for in Article 47 of the Charter of Fundamental Rights of the European Union (the ‘Charter’). They state that they followed the pre-litigation procedure laid down in Article 90(2) of the Staff Regulations.

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41) As regards, first, the alleged infringement of Article 47 of the Charter, it should be borne in mind that that article is not intended to change the system of judicial review laid down by the Treaties, and particularly the rules relating to the admissibility of direct actions brought before the Courts of the European Union, as is apparent also from the Explanation on Article 47 of the Charter, which must, in accordance with the third subparagraph of Article 6(1) TEU and Article 52(7) of the Charter, be taken into consideration for the interpretation of the Charter (see judgment of 4 June 2015, Andechser Molkerei Scheitz v Commission, C‑682/13 P, not published, EU:C:2015:356, paragraph 29 and the case-law cited).

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51) The applicants put forward three pleas in law in support of their action. The first plea alleges infringement of the right of collective action and the right to be informed and consulted, as enshrined in Articles 27 and 28 of the Charter and in Directive 2002/14/EC of the European Parliament and of the Council of 11 March 2002 establishing a general framework for informing and consulting employees in the European Community — Joint declaration of the European Parliament, the Council and the Commission on employee representation (OJ 2002 L 80, p. 29), implemented by the framework agreement of 12 July 1990 between the Parliament and the TUSAs of the institution’s staff (the ‘framework agreement’), and infringement of the right to good administration as enshrined in Article 41 of the Charter. The second plea alleges lack of competence on the part of the authority that adopted the measure and infringement of the principle of legal certainty, and the third plea alleges infringement of the right to an effective remedy, as provided for in Article 47 of the Charter.

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53) As regards the first part, the applicants claim that the right to strike is a fundamental right enshrined, in particular, in the Charter and in the European Social Charter signed in Turin on 18 October 1961, as revised. They acknowledge, however, that such a right is not absolute, that it must observe the principle of proportionality and that the exercise of that right may be subject to restrictions. They submit that neither Article 55 of the Staff Regulations, which does not cover minimum service in the event of a strike, nor the framework agreement or the decision of 2 July 2018 can serve as law, within the meaning of Article 52(1) of the Charter, which permits limitations on the right to strike. The applicants claim that it is commonly accepted that the right to strike in the public sector must be weighed against the need to guarantee essential services. They refer to the Committee on Freedom of Association of the International Labour Organisation (ILO), which distinguishes essential services from other services. They point out that the Parliament has never established clear and unambiguous rules to determine which services may prove to be essential in order to ensure continuity of service. According to the applicants, if such rules had already been established, that would have made it possible to demonstrate, first, the legitimacy of the objective pursued and, secondly, the necessity of the restriction. In the present case, according to the applicants, the decision of 2 July 2018 does not pursue a legitimate objective and is disproportionate.

54) The Parliament responds that it does not dispute the fact that the right to strike is a fundamental right enshrined in Article 28 of the Charter. It points out that the Staff Regulations do not deal with the right to strike and that the European Union is not, in principle, bound by any of the legal documents emanating from the ILO, given that the European Union is not a member of the ILO. It adds that, contrary to what the applicants claim, Article 55(1) of the Staff Regulations must be regarded as a limitation on the right to strike provided for by law within the meaning of Article 52(1) of the Charter and therefore constitutes the provision of the Staff Regulations that can serve as the basis for the requisitions. The Parliament submits that such requisitions are justified where strike action has the effect, and indeed the purpose, of disrupting its work as legislator, budgetary authority and supervisory authority. Those measures are therefore necessary within the meaning of Article 52(1) of the Charter. As regards the proportionality of the requisitions in the decision of 2 July 2018, the Parliament states that, throughout the strike action, it increasingly refined the requirements for the provision of a minimal interpretation service. It concludes that the decision of 2 July 2018 cannot seriously be challenged from the point of view of proportionality.

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56) In that regard, it follows from Article 28 of the Charter that workers and employers, or their respective organisations, have, in accordance with EU law and national laws and practices, the right to negotiate and conclude collective agreements at the appropriate levels and, in cases of conflicts of interest, to take collective action to defend their interests, including strike action.

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58) Moreover, Article 52(1) of the Charter provides that any limitation on the exercise of the rights and freedoms recognised by the Charter must be provided for by law and respect the essence of those rights and freedoms. Subject to the principle of proportionality, limitations may be made only if they are necessary and genuinely meet objectives of general interest recognised by the Union or the need to protect the rights and freedoms of others.

59) It follows from that article that, to be regarded as complying with EU law, a limitation on a right protected by the Charter must, in any event, satisfy three conditions (see, to that effect, judgment of 28 May 2013, Trabelsi and Others v Council, T‑187/11, EU:T:2013:273, paragraph 78).

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63) It is in the light of those considerations that it is necessary to examine whether the decision of 2 July 2018 constitutes a limitation on the right to strike as protected by Article 28 of the Charter and, if so, whether the three conditions necessary for such a limitation to comply with EU law are satisfied in the present case.

64) The Court considers that, in so far as it restricts the possibility for the interpreters concerned by the requisition measure of taking part in the collective and concerted cessation of work in defence of their interests, the decision of 2 July 2018 constitutes a limitation on the exercise of the right to strike guaranteed by Article 28 of the Charter. Moreover, the Parliament does not dispute that conclusion, submitting, however, that that limitation complies with EU law.

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66) As regards the condition that the limitation be ‘provided for by law’, it should be recalled that the requirement that any limitation on the exercise of the right guaranteed by the Charter must be provided for by law means that the legal basis must be sufficiently clear and precise and that, by defining itself the scope of the limitation on the exercise of that right, it affords a measure of legal protection against any arbitrary interferences by those authorities (see, to that effect, judgment of 17 December 2015, WebMindLicenses, C‑419/14, EU:C:2015:832, paragraph 81).

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70) Secondly, it should be noted that, although the decision of 2 July 2018 refers to Article 55 of the Staff Regulations in its entirety, the Parliament states that there was never any question of basing that decision on paragraphs 2, 3 or 4 of Article 55, but only on paragraph 1 of that article, which is autonomous in scope, independent of the respective fields of application of the other paragraphs. In any event, paragraphs 2, 3 or 4 of Article 55 of the Staff Regulations do not provide for the use of requisitions, with the result that they cannot serve as law within the meaning of Article 52(1) of the Charter.

71) It is therefore necessary to examine whether Article 55(1) of the Staff Regulations, on the one hand, or the framework agreement, on the other, could provide a legal basis for the decision of 2 July 2018 for the purposes of Article 52(1) of the Charter.

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74) The Parliament’s argument that Article 55(1) of the Staff Regulations allows the institution to call on officials outside working hours and to put the interests of the service before any consideration relating to normal working hours or leave cannot call that conclusion into question. Such an argument cannot succeed in view of the requirement, laid down by the Charter, to restrict the exercise of a right guaranteed by the Charter only by means of law that is sufficiently clear and precise, and which itself establishes the scope of the limitation on the exercise of the right at issue.

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78) Consequently, even if officials were able to derive rights from the infringement of the provisions governing the relations of the institutions with the TUSAs, Article 8 of the framework agreement could not, given that the protocol to which it refers was never adopted, in any event serve as law within the meaning of Article 52(1) of the Charter.

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81) It follows from all the foregoing that the requisition measures at issue constitute a limitation on the right to strike that was not provided for by law. The decision of 2 July 2018 must therefore be annulled, in so far as it infringes that fundamental right, without it being necessary to examine the other two conditions laid down in Article 52(1) of the Charter and referred to in paragraphs 61 and 62 above, and the other pleas in law raised by the applicants.