All nationals of a Member State are Union citizens, and so, in principle, these citizens fall within the scope of European Union (EU) law ratione personae. However, the protection of European citizenship status (ECS) is a necessary but not a sufficient condition for enjoying European citizenship rights (ECRs). In order to bring a case within its jurisdiction, the Court of Justice of the European Union (CJEU) should also ascertain what the link is between ECRs and the scope of EU law (ratione materiae). Recently, the CJEU ruled that securing the “genuine enjoyment of the substance of the rights attaching to the status of European Union citizenship” is a sufficient condition to bring a case within the scope of EU law. This new formula challenges the traditional cross-border test: by referring to “genuine enjoyment,” it entails rethinking the CJEU's current practice of depicting the conditions under which a citizenship case should be considered ratione personae and ratione materiae within the scope of EU law. Importantly, the interpretative crux of this new formula concerns whether the Court has really opted for an innovative test of its jurisdiction, which may detach the protection of ECRs from the current exercise of fundamental freedoms. This paper critically maps out how the CJEU has gradually strengthened both the protection of the ECS and the protection of rights attaching to such status. It argues that the Court has recognized that the de facto exercise of fundamental freedoms is not the only way to establish a link between a EU citizenship case and the scope of EU law. On the contrary, the Court ruled that Art. 20 TFEU (on Union citizenship and European citizenship rights) can be invoked by Union citizens, even if they have never exercised their free movement rights, in order to challenge national measures, which “deprive citizens of the Union of the genuine enjoyment of the substance of the rights conferred by virtue of their status as citizens of the Union.” This interpretative move raises the question whether the new test concerning the substance of the rights attaching to the status of European citizens enhances the protection of fundamental freedoms, by also safeguarding the potential exercising of these freedoms in the future, or whether it calls for including the actual protection of fundamental rights (such as the right to respect family life) in the so-called “substance” of European citizenship rights. This paper argues that the Court's present approach indicates that the former is the case, casting doubts on the central position of fundamental rights with regards to European citizenship.