Judgment of the Court (Fifth Chamber) of 7 September 2023.#RF v Finanzamt G.#Request for a preliminary ruling from the Bundesfinanzhof.#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.#Case C-15/22.