In the summer of 1960, Edgar Morin, a sociologist, and Jean Rouch conducted an enquiry into the daily lives of young Parisians in an attempt to understand their concept of happiness. This experimental film follows, over a period of a several months, both the investigation itself and the development of its main characters. The initial question “How do you live ? Are you happy ?” very quickly raises others on a number of key issues: politics, hopelessness, boredom, solitude… The interviewees eventually meet as a group at the first showing of the film, to discuss and approve or disapprove of it ; the two co-authors are confronted with the reality of this cruel but exciting experiment in “cinema-vérité”.