Within the unique story that is the European Union, the social dimension has undergone a major evolution. The national welfare state itself will become the object of the elaboration of the internal market, whereby European law will play a strong role in the development of social law, in particular through a negative integration movement. By encouraging freedom of movement, major competition arose between the different legislations of the Member States, with the key question being which legislation is applicable to migrants in a cross-border situation. This has led to concerns often described as manifestations of social dumping. In addition the question arises how to improve the enforcement of European social law. Enforcement is often the soft underbelly of European social law. Without proper enforcement, social dumping can be rampant