Professeur émérite de l’Université Libre de Bruxelles; Président de la Fondation Chaïm Perelman; Visiting Professor of Law, Duke University, USA (1985-2010); Recurrent Visiting Professor, Central European University, Budapest (1992-2010); Professor, Inter-European Institute for Human Rights and Democratization (EIUC), Venice: Visiting Professor, University of International Business and Economics (UIBE), Beijing, 2015.