Having started his career at Paris-Match in 1970, he joined Le Point in 1972, in 1988 he became editor-in-chief, as well as editor-in-chief of the political and cultural staffs. In 1995, Jeambar became general director of Europe 1 and after a few months, in 2001 he became president of the directory of Groupe Express-Expansion. In August 2006, he director of Seuil editions. He has been a member of Le Siècle, nos enfants nous haïront with Jacqueline Rémy, Éditions du Seuil,2006 Le défi du monde with Claude Allègre, Fayard,2006 Accusé Chirac, levez vous