I began my career as a research fellow at CERMAP (Centre d'études et de recherches mathématiques appliquées à la planification), then at CEPREMAP (Centre d'études prospectives et de recherches en économie mathématique appliquée à la planification). I was successively Research Fellow, Senior Scientist and Director of Research (exceptional class from 1996-2000) at the CNRS.

More by taste than necessity, I have in the past held teaching posts, both temporarily in France at several grandes écoles and Parisian universities, and abroad, as Lent term professor at the London School of Economics and at several American universities (Pennsylvania, Harvard), and more permanently at EHESS, the École des hautes études en sciences sociales, where I have been Director of Studies (cumulant) since 1979.

At the Collège de France, teaching has become my main occupation. My opening lecture was published in the Revue d'Économie politique (2002) under the title " L'État et le marché : constructions savantes et pensée spontanée ", (119), 6, November-December 2002, p. 799-814. Participation in research facilitation activities is a fairly long chapter of my activities. In particular, I co-founded DELTA (Département et laboratoire d'économie théorique et appliquée) with François Bourguignon, and was its director from 1991 to 2000. I was also, at the request of François Furet, then President of EHESS, the first person in charge of the doctoral program in Economic Analysis and Policy, from 1981 to 1991. I am currently Chairman of the Board of the Paris School of Economics. Economic policy advice is another area of activity : a recent avatar is my membership of the Conseil d'analyse économique.

The fact of having been a member of several editorial boards of renowned professional journals, and of having held positions of responsibility within learned societies, should undoubtedly be considered not only as an office but also as an honor and distinction. In particular, I was co-editor-in-chief of Econometrica (from 1984 to 1989), president of the European Economic Association (1994), president of the Econometric Society (1996) and of the Association Française de Sciences Économiques (2003). He has also been awarded the CNRS Silver Medal (1993), and has been Honorary Foreign Member of the American Economic Association (since 1997) and Member of the American Academy of Arts and Sciences (since 2000).

My publications are listed in full, under the following headings : general economic equilibrium, applied public economics, theoretical public economics (economic calculation, taxation and redistribution), economics of climate change, economics of incentives, endogenous fluctuations, rationality of expectations, and miscellaneous articles.