Charlotte Halpern is associate research professor in political science at Sciences Po, Centre d'Etudes Européennes (CEE), CNRS, Paris. Patrick Hassenteufel is professor in political science at the University of Versailles and Sciences Po Saint-Germain-en-Laye, Printemps (CNRS). Philippe Zittoun is research professor at LAET-ENTPE (University of Lyon) and General Secretary of the International Public Policy Association.