On a hot summer day along the Seine embankment, a lonely retiree collapsed and died of a heart attack. The compassionate concierge is ready to arrange him a worthy funeral. But a photograph in the newspaper draws the attention of people who had known her boarder many years ago. Among them are high-society ladies and prostitutes, businessmen and drifters, adventurers and spies. Paris police lose their footing… Who is he, this modest Monsieur Bouvet?