The Charter of Fundamental Rights codifies and reaffirms the rights and principles recognised in European Union law. These rights and principles result from the constitutional traditions common to the Member States, the European Convention for the Protection of Human Rights and Fundamental Freedoms, the case law of the Court of Justice of the European Union and that of the European Court of Human Rights. The Charter was meant to strengthen the protection of fundamental rights and principles by making them more visible. This study explores the restrictions on the applicability of the rights and principles enshrined in the Charter. Given that the most problematic questions are those regarding the application of the Charter’s rights and principles by the Member States, it focuses on these questions and points out, when necessary, some other problems such as the distinction between rights and principles and their application in horizontal relations. The study also analyses the different modes and constraints of application of the Charter and interpretation of it by Member State courts. Finally, it examines whether the Charter, despite its limited scope of application, can provide national courts with new competences to apply the fundamental rights.