The precise legal classification of a letter or note is a matter for the Tribunal alone and not for the parties. A letter from an official which does not expressly request the withdrawal of the decision in question but is clearly intended to challenge a decision adversely affecting him constitutes a complaint within the meaning of Article 90(2) of the Staff Regulations. In that respect, the content of the act takes precedence over its form.

Although Article 85(1) of the Conditions of Employment of Other Servants provides for the possibility of a second renewal of contract, this is neither a right conferred on the member of staff concerned nor a guarantee of any continuity of employment, but a possibility subject to the discretion of the authority empowered to conclude contracts of employment. The institutions enjoy a wide discretion to organise their departments to suit the responsibilities entrusted to them and to assign their staff having regard to those responsibilities, provided, however, that that assignment is in the interests of the service.

However, Article 6(2) of the Decision of the Administrative Board of the Agency for the Cooperation of Energy Regulators on the Adoption of General Implementing Provisions on the Procedures Governing the Engagement and the Use of Contract Staff at ACER makes the possibility of granting a second renewal of a contract for an indefinite period subject to the prerequisite that the combined duration of the initial contract and its first renewal must be at least five years. Where that prerequisite is not satisfied, any possibility of renewal, on request or even at the institution’s own motion, is mandatorily excluded.

Where an institution or an agency is authorised to lay down general implementing provisions intended to supplement or implement hierarchically superior and binding provisions of the Staff Regulations or the Conditions of Employment of Other Servants, the competent authority may neither act contra legem, in particular by adopting provisions whose application would be contrary to the aims of the provisions of the Staff Regulations or would render them entirely ineffective, nor fail to comply with general legal principles such as the principle of sound administration, the principle of equal treatment and the principle of the protection of legitimate expectations.

Thus, Article 6(2) of the Decision restricts the scope of Article 85(1) of the Conditions of Employment of Other Servants in so far as it introduces a supplementary condition for the renewal of a contract as a member of the contract staff within the meaning of Article 3a of the Conditions of Employment which is not provided for in the Conditions of Employment and which hinders the exercise of the discretion conferred on the administration, without such a restriction being objectively justifiable in the interests of the service. An internal decision of an agency which is general in scope, such as a decision on general implementing provisions, cannot lawfully restrict the scope of an explicit rule laid down in the Staff Regulations or the Conditions of Employment of Other Servants, unless it has been stipulated that this is expressly authorised.

(see paras 51-53, 56)

Judgments in Commission v Petrilli, T‑143/09 P, EU:T:2010:531, paras 31 and 34 to 36 and the case-law cited therein, and Commission v Macchia, T‑368/12 P, EU:T:2014:266, paras 49 and 60