54It must be noted that that argument is inconsistent with what the applicant has also maintained in its various pleadings, that is to say that it actively participated in the administrative procedure relating to concentration M.8871. The applicant cannot maintain its line of argument that it actively participated in the procedure and, at the same time, criticise the Commission, for the first time at the hearing, for not having set a time limit for it to submit its observations, in order to establish its standing to bring proceedings. By virtue of the judge-made principle nemo potest venire contra factum proprium, also known as venire contra factum proprium non valet, a person may not dispute what he or she has previously accepted (judgments of 22 April 2016, Ireland and Aughinish Alumina v Commission, T‑50/06 RENV II and T‑69/06 RENV II, EU:T:2016:227, paragraph 192, and of 6 April 2017, Regione autonoma della Sardegna v Commission, T‑219/14, EU:T:2017:266, paragraph 63; see also, to that effect, order of 13 February 2014, Marszałkowski v OHIM, C‑177/13 P, not published, EU:C:2014:183, paragraph 73). That argument must therefore be rejected as manifestly inadmissible.