Judgment of the Court (Grand Chamber) of 15 June 2021.#Facebook Ireland Ltd and Others v Gegevensbeschermingsautoriteit.#Reference for a preliminary ruling – Protection of natural persons with regard to the processing of personal data – Charter of Fundamental Rights of the European Union – Articles 7, 8 and 47 – Regulation (EU) 2016/679 – Cross-border processing of personal data – ‘One-stop shop’ mechanism – Sincere and effective cooperation between supervisory authorities – Competences and powers – Power to initiate or engage in legal proceedings.#Case C-645/19.