Pursuant to Article 263 TFEU, the Court of Justice reviews the legality of acts of the Commission. Since its creation in 1988, the General Court exercises that review in the first instance. An action for annulment of a Commission decision on State aid is subject to a number of conditions:

– Challengeable acts: as a principle, decisions on State aid may be subject to action for annulment. Such is the case for a decision not to raise any objections, an order to provide information, a decision to initiate the formal procedure, insofar as it implies to classify aid as existing or new aid, suspension decision, decision proposing to adopt appropriate measures and final decision. To be classified as a challengeable act, the act must unequivocally adopt a measure which produces legal effects affecting the interests of the parties concerned by bringing about a change in their legal position and which is binding on them. The Commission’s letters merely supplying information therefore do not constitute actionable measures. Likewise, acts purely confirmatory and preparatory measures are inadmissible on that basis. Although producing legal effects, a compatibility decision is not prejudicial to the recipient State, which therefore has no right of appeal. On the other hand, a letter by which the Commission decides not to pursue a complaint because there are insufficient grounds and merely informs the complainant that the aid complained of is existing aid, is also a decision open to challenge insofar as it refuses by implication to initiate the formal investigation procedure.

– Interest in bringing proceedings: only natural or legal persons to whom a decision is addressed or those who are directly and individually affected by that decision are entitled to institute proceedings. Any other applicant must, by contrast, bring evidence of a direct and individual interest in bringing proceedings. This is the case of the recipient of the aid and its competitors. The beneficiaries of an unlawful aid, who were fully identifiable when the incompatibility decision was adopted, are individually concerned by virtue of this capacity alone. The actual beneficiary has an individual interest in bringing proceedings, but not the potential recipient. In all cases, the applicant must have a vested and present interest in the annulment of the contested act. This is the case for minority shareholders of the beneficiary of aid declared compatible under certain conditions, insofar as the contested decision adversely affects their property rights. The question is more complex for competing undertakings. The capacity as undertaking competing with the beneficiary, whose interests could be affected, is sufficient to give it standing to challenge a compatibility decision taken on conclusion of the preliminary phase, where due to the absence of initiation of a formal procedure it was not given the opportunity to assert its rights. By contrast, the capacity as competitor is insufficient to show an interest in bringing proceedings where the decision was adopted on completion of the formal investigation phase. The beneficiary’s competitor must then justify – given the extent of its possible participation in the procedure and the significant effect on its market position – circumstances which distinguish it individually just as in the case of the person addressed. A decision declaring aid to be incompatible may also be the subject of a claim for annulment by the competitor where the decision does not appropriately protect the competitor’s legal situation and where unlawful aid remains. Lastly, a professional association, which constitutes one of the interested parties listed in Article 1 of Regulation No 2015/1589, can be recognized an own interest in bringing proceedings where it has the capacity as negotiator, within an economic meaning, in the sector concerned or it represents undertakings whose action would have been individually admissible, or a collective interest associated to its participation in the proceedings.

– Review of the action: Article 263 TFEU sets out five grounds for annulment, namely lack of competence and infringement of essential procedural requirements concerning the external legality of the decision, infringement of a rule of law, infringement of the Treaty and misuse of powers which make it possible to review the internal legality. The court cannot however raise a plea of its own motion based on an infringement of Article 107(1) TFEU because of the non-imputability of the measure in question to a Member State, where that plea goes to the substantive legality of the contested decision. The broad discretion that the Commission has for the review of State aid, the exercise of which involves economic and social assessments which must be made in an EU context, limits the power of the court which can only carry out a limited review. By contrast, the objective nature of the classification as new or existing aid, within the meaning of Article 107(1), implies a maximum review by the court.

– Limitation period: the starting point of the time-limit for bringing proceedings set forth in Article 263(5) TFEU is, as a principal matter, that of publication or notification of the act, and, as a subsidiary matter, that of the date on which it came to the applicant’s knowledge. The publication for information on the internet, provided for in Article 10 of Regulation No 794/2004 is valid as publication as regards the starting point of the time-limit. The applicant who learned of a decision of incompatibility of a State aid prior to its publication benefits nevertheless from a time-limit for bringing proceedings of two months from the publication. The EU institutions are not required to inform the parties of existing remedies or of time-limits for exercising them. At the end of that period, the decision is final and can no longer be contested.

– Effects of the action: if  the action is well founded, the challenged measure is declared to be void (Article 264 TFEU). The annulment decision has authority erga omnes. The institution whose act has been annulled is required to give all the effects to the annulment (Article 266 TFEU) and must take the necessary measures to fully apply the decision. Where a Commission’s decision is annulled, the Commission is required to start its review from the point that unlawfulness took place. In so doing, it is subject to a duty to act within a reasonable period, determined according to the complexity of the case. The annulment of the initial approval decision removes all legal basis from decisions made to apply it. Although the applicant cannot rely on factual arguments which were unknown to the Commission and which it had not notified to the latter during the examination procedure, it can raise against its final decision a legal plea not raised at the stage of the administrative procedure.