Judgment of the Court (Grand Chamber) of 4 July 2023.#Meta Platforms Inc and Others v Bundeskartellamt.#Reference for a preliminary ruling – Protection of natural persons with regard to the processing of personal data – Regulation (EU) 2016/679 – Online social networks – Abuse of a dominant position by the operator of such a network – Abuse which entails the processing of the personal data of the users of that network as provided for in its general terms of use – Powers of a competition authority of a Member State to find that processing not consistent with that regulation – Reconciliation with the powers of the national data protection supervisory authorities – Article 4(3) TEU – Principle of sincere cooperation – Points (a) to (f) of the first subparagraph of Article 6(1) of Regulation 2016/679 – Whether the processing is lawful – Article 9(1) and (2) – Processing of special categories of personal data – Article 4(11)