Case C-15/22, Finanzamt G (Development aid projects): Judgment of the Court (Fifth Chamber) of 7 September 2023 (request for a preliminary ruling from the Bundesfinanzhof — Germany) — RF v Finanzamt G (Reference for a preliminary ruling — Development cooperation — Direct taxation — Income tax — Exemption granted to employees assigned to development aid projects financed from national budgetary resources — Difference in treatment of employees assigned to a project financed by the European Development Fund — Article 63(1) TFEU — Free movement of capital — Article 4(3) TEU — Duty of sincere cooperation — Facilitating the tasks of the European Union — Articles 208 and 210 TFEU — Development cooperation — Obligation to promote policies in the area of development cooperation — Invocability)