This thesis explores the notion of barrier to intra-Community trade and movement as developed by the European Court of Justice. Through a critical assessment of the case law, it aims at identifying the content of the rights granted by the free movement provisions and at providing a normative justification capable of accommodating the evolution of the Court's interpretation. Thus, it is argued that some of the recent case law can be better explained having regard to the notion of the fundamental right to exercise an economic activity free of unjustified and disproportionate restrictions. Further, other problematic strands of case law can be better explained having regard to the fundamental rights discourse. The thesis therefore challenges the traditional doctrinal approaches to the free movement provisions, to suggest that the broad interpretation currently adopted by the Court in this field cannot be justified having sole regard to a Ideological interpretation of the free movement provisions. Instead, it suggests that the developments in the case law should be appreciated in the context of the constitutional changes which have occurred in the past decade in the European Union. Thus, it links the extensive interpretation given to the free movement of persons provisions, to the introduction of Union citizenship, to argue that the normative justification for the Court's case law is better found in a joint reading of the free movement of persons and Union citizenship provisions. Thus, the extensive approach adopted in the field of free movement of persons signals the emergence of a new constitutional dimension whereby the individual is protected also qua citizen, rather than just qua economic actor.