26In the context of the review procedure referred to in Article 108 TFEU, two stages must be distinguished. First, the preliminary examination stage provided for in Article 108(3) TFEU, which allows the Commission to form a prima facie opinion on the conformity of the aid in question. Second, the formal investigation procedure provided for in Article 108(2) TFEU, which allows the Commission to be fully informed of the facts of the case. It is only in the context of that procedure that the FEU Treaty imposes an obligation on the Commission to give the parties concerned notice to submit their comments (judgments of 19 May 1993, Cook v Commission, C‑198/91, EU:C:1993:197, paragraph 22; of 15 June 1993, Matra v Commission, C‑225/91, EU:C:1993:239, paragraph 16; and of 15 October 2018, Vereniging Gelijkberechtiging Grondbezitters and Others v Commission, T‑79/16, not published, EU:T:2018:680, paragraph 46).