English summary: The liberalization of public services is subject to heated political debate. Sven Simon analyzes the liberalization structure in the two relevant treaties and explores the question of whether or not public services are inevitably subject to liberalization in WTO or EU law. He addresses the complex constitution of the GATS, discusses the scope of the application as well as the potential justification for restrictions with regard to the single market in the EC Treaty, and evaluates the effects of the new protocol concerning public services included in the Lisbon Treaty. The...