1 This request for a preliminary ruling concerns the interpretation of Article 20 TFEU. 2 The request has been made in proceedings between JY and the Wiener Landesregierung (Government of the Province of Vienna, Austria) concerning the latter’s decision to revoke the assurance as to the grant of Austrian nationality to JY and reject JY’s application to obtain that nationality. Legal context International law Convention on the Reduction of Statelessness 3 Article 7(2) of the United Nations Convention on the Reduction of Statelessness, which was adopted in New York on 30 August 1961 and entered into force on 13 December 1975 (‘the Convention on the Reduction of Statelessness’), provides: ‘A national of a Contracting State who seeks naturalisation in a foreign country shall not lose his nationality unless he acquires or has been accorded assurance of acquiring the nationality of that foreign country.’ The European Convention on Nationality 4 The European Convention on Nationality, adopted on 6 November 1997 within the framework of the Council of Europe, entered into force on 1 March 2000 and has been applicable to the Republic of Austria since that date. 5 Under Article 4 of that convention, headed ‘Principles’: ‘The rules on nationality of each State Party shall be based on the following principles: a everyone has the right to a nationality; b statelessness shall be avoided; …’ 6 Article 7 of that convention, headed ‘Loss of nationality ex lege or at the initiative of a State Party’, provides: ‘1 A State Party may not provide in its internal law for the loss of its nationality ex lege or at the initiative of the State Party except in the following cases: a b voluntary acquisition of another nationality; acquisition of the nationality of the State Party by means of fraudulent conduct, false information or concealment of any relevant fact attributable to the applicant; … d conduct seriously prejudicial to the vital interests of the State Party; … 3 7 A State Party may not provide in its internal law for the loss of its nationality under paragraphs 1 and 2 of this article if the person concerned would thereby become stateless, with the exception of the cases mentioned in paragraph 1, sub-paragraph b of this article.’ Article 8 of the convention, which is entitled ‘Loss of nationality at the initiative of the individual’, provides, in paragraph 1 thereof: