Medical doctor, specialized in tropical medicine, emergency medicine and epidemiology. In 1989 he went on mission with Médecins sans Frontières for the first time, and undertook long-term missions in Uganda, Somalia and Thailand. He returned to the Paris headquarters in 1994 as a programs director. Between 1996 and 1998, he served as the director of communications, and later as director of operations until May 2000 when he was elected president of the French section of Médecins sans Frontières. He was re-elected in May 2003 and in May 2006. From 2000 to 2008, he was a member of the International Council of MSF and a member of the Board of MSF USA. He is the co-editor of "Medical innovations in humanitarian situations" (MSF, 2009) and Humanitarian Aid, Genocide and Mass Killings: Médecins Sans Frontiéres, The Rwandan Experience, 1982–97 (Manchester University Press, 2017).

Medical doctor, specialized in tropical medicine and epidemiology. Involved in humanitarian action since 1977, he has been on numerous missions, mainly in contexts of armed conflicts and IDP situations. President of Médecins sans Frontières from 1982 to1994, he also teaches at the Humanitarian and Conflict Response Institute (HCRI) and is a regular contributor to Alternatives Economiques. He has published several books and articles, including "Guerre humanitaires ? Mensonges et Intox" (Textuel, 2018), "La Médecine Humanitaire" (PUF, 2010), "Penser dans l'urgence" (Editions du Seuil, 2006) and "Utopies Sanitaires" (Editions Le Pommier, 2000).