CURIA - Documents 11 of 11 https://curia.europa.eu/juris/document/document_print.jsf?docid=753... naturalisation when that nationality has been obtained by deception, on condition that the decision to withdraw observes the principle of proportionality. The second part of the second question 60 By the second part of the second question the national court asks, in essence, whether, when a citizen of the Union in a situation such as that of the applicant in the main proceedings is faced with a decision withdrawing naturalisation that threatens to lead to the loss of his status of citizen of the Union, European Union law, in particular Article 17 EC, must be interpreted as meaning that the Member State whose nationality he originally possessed is obliged to interpret its domestic legislation in such a way as to avoid that loss by allowing him to recover that nationality. 61 In this instance, it is to be noted that the withdrawal of the naturalisation acquired by the applicant in Germany has not become definitive, and that no decision concerning his status has been taken by the Member State whose nationality he originally possessed, namely, the Republic of Austria. 62 It is to be borne in mind, in these proceedings for a preliminary ruling, that the principles stemming from this judgment with regard to the powers of the Member States in the sphere of nationality, and also their duty to exercise those powers having due regard to European Union law, apply both to the Member State of naturalisation and to the Member State of the original nationality. 63 The Court cannot, however, rule on the question whether a decision not yet adopted is contrary to European Union law. As the Austrian Government maintained at the hearing, the Austrian authorities will possibly have to adopt a decision on the question whether the applicant in the main proceedings is to recover his nationality of origin and when that decision has been adopted the Austrian courts will, if necessary, have to determine whether it is valid in the light of the principles referred to in this judgment. 64 Having regard to the foregoing there is no need in these proceedings to give a ruling on the second part of the second question. Costs 65 Since these proceedings are, for the parties to the main proceedings, a step in the action pending before the national court, the decision on costs is a matter for that court. Costs incurred in submitting observations to the Court, other than the costs of those parties, are not recoverable. On those grounds, the Court (Grand Chamber) hereby rules: It is not contrary to European Union law, in particular to Article 17 EC, for a Member State to withdraw from a citizen of the Union the nationality of that State acquired by naturalisation when that nationality was obtained by deception, on condition that the decision to withdraw observes the principle of proportionality. [Signatures] * Language of the case: German. 26/05/2021, 10:03