[en] A case study of community law comes to the following results: 1) The Single European Act is to improve, and not impair, the state of integration in the EC achieved so far. 2) National limitations of transboundary, free service transactions are only allowed on national territories in the interest of protecting the population against health hazards. 3) True to say, there are no properly formulated European basic rights, but there is an unwritten, by the European Court of Justice accepted European basic rights catalogue, which resembles German basic rights. 4) Primary and secondary EC community law has priority over corresponding national law. 5) Prior-ranking of European law does not mean voidness of corresponding national law, but lower priority, always related to individual cases. 6) Prior-ranking of EC community law commits those in Federal Government and Laender authorities and in the courts who are concerned with the application of law, to interprete German law in a way conform with Community law. (orig./HSCH)