Judgment of the Court (Grand Chamber) of 12 March 2019.#M.G. Tjebbes and Others v Minister van Buitenlandse Zaken.#Reference for a preliminary ruling — Citizenship of the European Union — Article 20 TFEU — Articles 7 and 24 of the Charter of Fundamental Rights of the European Union — Nationalities of a Member State and of a third country — Loss of the nationality of a Member State and of citizenship of the Union by operation of law — Consequences — Proportionality.#Case C-221/17.