Like Article 90(2) of the Staff Regulations, paragraph 42 of the Conditions of Employment and Article 8.1 of the Staff Rules of the European Central Bank state that ECB staff may bring legal proceedings only after exhausting the pre-litigation procedure, which, as regards ECB staff, is in two stages: a request for pre-litigation review and then a preliminary complaint.

The legality of the definitive act adversely affecting the applicant is assessed in the light of the elements of fact and of law available to the institution on the adoption, whether express or implied, of that response, without prejudice to the possibility, for the institution to provide supplementary explanations during the contentious stage. The rule of correspondence between the complaint and the subsequent action requires that, for a plea before the Courts of the European Union to be admissible, it must have already been raised in the pre-litigation procedure, thus enabling the appointing authority to know in sufficient detail the criticisms made of the contested decision.

In actions brought by officials, claims before the Courts of the European Union may contain only heads of claim based on the same matters as those raised in the complaint, although those heads of claim may be developed before the Courts of the European Union by the presentation of pleas in law and arguments which, whilst not necessarily appearing in the complaint, are closely linked to it.

However, first, since the pre-litigation procedure is informal in character and those concerned are acting without the assistance of a lawyer at that stage, the administration must not interpret the complaints restrictively but must, on the contrary, examine them with an open mind. Secondly, it is not the purpose of Article 91 of the Staff Regulations, the corresponding provisions of the Conditions of Employment or Article 8.1 of the Staff Rules, to bind strictly and absolutely the contentious stage of the proceedings, if any, provided that the action changes neither the legal basis nor the subject matter of the complaint.

Whilst it is necessary that the subject-matter and cause of action of the dispute remain unchanged between the complaint and the action in order to allow an amicable settlement of the dispute, by informing the appointing authority of the applicant’s criticisms at the complaint stage, the interpretation of those concepts must not have the effect of restricting the scope for the person concerned effectively to challenge a decision adversely affecting him.

Consequently, the concept of the subject-matter of the dispute, which corresponds to the claims of the person concerned, and the concept of cause of action, which corresponds to the legal and factual basis for those claims, must not be interpreted restrictively. Merely changing the legal basis of a dispute is not sufficient to characterise it as having a new cause of action. There may be a number of legal bases supporting a single claim and, consequently, a single cause of action. In other words, relying in the application on the infringement of a specific provision which was not relied on in the complaint does not necessarily mean that the cause of action of the dispute has thereby been altered. Consideration must be given to the substance of the cause of action and not merely to the wording of its legal bases, and the Union judicature must ascertain whether there is a close connection between its bases and whether they essentially relate to the same claims.

(see paras 32-40)