International Organizations (lectures at the Katholieke Universiteit Leuven, 2010)

The transatlantic divide over international law (seminar series at the Moritz College of Law, The Ohio State University, 2008)

The collective non-recognition of illegal States (seminar series at the University Paris II  - Panthéon Assas, 2006)

Treaty relations of the EC/EU and its member states (seminar series at Yeditepe University, Istanbul, 2003)

Between world state and world society – new models of transnational governance (Seminar series with Axel Kämmerer at the Summer School of the German National Scholarship Foundation, 2002)

The impact of European Community/Union law on German constitutional law (seminar series at the University Aix-Marseille III, 2002)

Current problems of international law (lectures at the University Aix-Marseille III, 2001)

The procedural law of the German constitutional court at the Jaroslaw-Mudrj Academy Charkow, Ukraine, 2000)