Refusal by a Member State to register a child with the surname it would have under the rules of the Member State of origin of the parents. Discrimination on the basis of nationality.
Art. 18 TFUE
Art. 20 TFUE
Art. 21 TFUE
1. Nationals of one Member State who are lawfully resident in the territory of another Member State may rely on the right set out in Article 12 EC not to suffer discrimination on grounds of nationality in regard to the rules governing their surname. Citizenship of the Union is destined to be the fundamental status of nationals of the Member States, enabling those nationals who find themselves in the same situation to enjoy, within the scope ratione materiae of the EC Treaty, the same treatment in law irrespective of their nationality, subject to such exceptions as are expressly provided for.
2. Although the principle of the immutability of surnames, as a means designed to prevent risks of confusion as to identity or parentage of persons, undoubtedly helps to facilitate recognition of the identity of persons and their parentage, it is still not indispensable to the point that it could not adapt itself to a practice of allowing children who are nationals of one Member State and who also hold the nationality of another Member State to take a surname which is composed of elements other than those provided for by the law of the first Member State and which has, moreover, been entered in an official register of the second Member State. Furthermore, by reason in particular of the scale of migration within the Union, different national systems for the attribution of surnames coexist in the same Member State, with the result that parentage cannot necessarily be assessed within the social life of a Member State solely on the basis of the criterion of the system applicable to nationals of that latter State. In addition, far from creating confusion as to the parentage of the children, a system allowing elements of the surnames of the two parents to be handed down may, on the contrary, contribute to reinforcing recognition of that connection with the two parents.