Judgment of the Court (Seventh Chamber) of 16 November 2023.#JD v Acerta - Caisse d'assurances sociales ASBL and Others.#Reference for a preliminary ruling – Officials of the European Union – Staff Regulations of Officials of the European Union – Compulsory affiliation to the social security scheme of the EU institutions – Retired official of the European Union who pursues a professional activity as a self-employed person – Liability for social security contributions under the scheme of the Member State in which that activity is carried out.#Case C-415/22.