"Le Tambourin", a Montmartre nightclub, is on its way down. Although it can boast great performances by the alluring Les Bluebell Girls and by Jacques Hélian's lively Big Band the venue does not attract people anymore. Nightclub patrons now prefer the jazz cellars of Saint-Germain-des-Prés. Taking this new taste into account, the staff of the "Tambourin" and Jacques Hélian decide to set up their own club, "La Pivoine Ecarlate". They are joined by Pâquerette, a flower vendor and amateur singer, and by Jean-Pierre Francis, an existentialist poet...