A geographer and urbanist, he teaches at the École Polytechnique Fédérale de Lausanne (EPFL) and Rheims University, and he is also a member of the Chôros research network. His major study areas include the social theory of space, political geography, globalisation and the epistemology of social sciences. He has conducted numerous research projects on metropolises worldwide and completed several practical urban and territorial projects.

He has been a scientific advisor for the French Ministry of Research (Direction de la Recherche, 2000-2003) and an invited professor at various universities: UCLA, NYU, USP (São Paulo), L’Orientale (Naples), Macquarie (Sydney), the University of Bergamo and the Reclus Chair in Mexico City. He has participated as a keynote speaker at many congresses and conferences around the world, and he has authored over 700 publications. Having been a member of many scientific committees, today he is co-editor of EspacesTemps.net, a  journal of social sciences, as well as scientific advisor for the Pouvoirs Locaux journal.