Conference announcement: 30 Years of Game Theory at Institut Henri Poincaré, October 06-10, 2025, Paris.

Welcome

The Séminaire parisien de Théorie des Jeux is an open, inter-institutional, multi-disciplined seminar which covers all fields of game theory. It takes place on Monday from 11:00 to 12:00 am at Institut Henri Poincaré, 11 rue Pierre et Marie Curie, Paris 5ème. MAP

You will find the program for the current academic year on the page 2025/2026 and the program for past years on the page Archives.

The junior seminar welcomes PhD students in game theory to present their work.  You will find the program for the current academic year on the page Junior Seminar 2025/2026.

Next seminar:  

April 13th, 2026 (room Maryam Mirzakhani 201): 

Julien COMBE (CREST, Ecole polytechnique)

Title : "Optimal mechanisms under paternalism: sin taxes, rationing and prohibition" (joint work with Yves Le Yaouanq)

Abstract: ​​​​​Many economic transactions are banned or regulated due to paternalistic considerations. We incorporate paternalistic motives into a mechanism design framework. A planner seeks to organize trade between a continuum of buyers and sellers with private information about their valuation for a good. The planner's normative assessment of each transaction might differ from the agents' decision utility, as she believes that individuals do not act in their best interest. We axiomatize a class of social welfare functions that reflect paternalistic concerns, and shows how it captures several popular models of behavioral bias. A key determinant of the optimal mechanism is whether the social planner's paternalistic motives preserve the ordering between agents with heterogenous valuations for the good. When it does, a ``sin tax'' is optimal and achieves the first-best. Otherwise, the optimal mechanism may ration one side of the market or even prohibit transactions, even when gains from trade exist under complete information. We discuss applications to repugnant markets and the regulation of sin goods.

Organizers

Frédéric Koessler (CNRS, HEC Paris), frederic.koessler[at]gmail[dot]com

Maël Letreust  (CNRS,  IRISA Rennes), mael.le-treust[at]cnrs[dot]fr

Chantal Marlats (LEMMA, Université Paris Panthéon-Assas), chantal.marlats[at]u-paris2[dot]fr

Yannick Viossat (CEREMADE, PSL), viossat[at]ceremade[dot]dauphine[dot]fr

To join (or unsuscribe from) our mailing list, please contact Maël Le Treust at mael.le-treust[at]cnrs[dot]fr. 

Former organizers

Joseph Abdou; Bernard De Meyer; Françoise Forges; Olivier Gossner;  Marie Laclau; Rida Laraki; Lucie Ménager; Vianney Perchet; Jérôme Renault; Dinah Rosenberg; Sylvain Sorin; Tristan Tomala; Xavier Venel; Nicolas Vieille; Guillaume Vigeral; Bruno Ziliotto