Cultural Diversity is an important political and legal topos in the European Union. At the same time, the concern for cultural diversity gives reason for grave reservations towards the Union. This article intends to assist, on the basis of international law, in distinguishing appearance and reality. The Union will be analyzed firstly as a situation of application of the international law of cultural diversity, secondly as regional executive of this international law, and thirdly as its global promoter. 
It shows that international law and Union law reinforce each other. The former conveys to the Union instruments to pursue European unification which at the same time serve its own implementation. Furthermore, it does not set limits to the European unity since it only protects cultural pluralism but not state-supporting distinctiveness. A prerequisite for this consonance is that the Union’s constitutional law allows for political unity without cultural unity and that international law remains mute about important questions on European unification. The international law perspective thus does not fully exhaust the problem: conformity with international law alone cannot dissipate the concern for the future of cultural diversity in the Union.