European Union – Freedom of movement. Article 21(1) of the Treaty on the Functioning of the European Union should be interpreted as not precluding legislation of a member state which did not provide for the grant of a derived right of residence in another member state, under Union law, to a third-country national family member of a Union citizen who was a national of that member state and who returned there after having resided, pursuant to and in conformity with Union law, in another member state, when the family member of the Union citizen concerned had not entered the territory of the member State of origin of the Union citizen or had not applied for a residence permit as a 'natural consequence' of the return to that member state of the Union citizen in question, provided that such rules required that other relevant factors also be taken into account. The Court of Justice so held in a preliminary ruling in proceedings concerning the Danish Immigration Office's decision to reject the first applicant's request for a residence permit in Denmark, as a family member of the second applicant, a Union citizen.