Marceline is pretty but inconstant. She has a brother, eccentric as well as invading, who serves as a go-between between the fickle young woman and her lovers. She has been the mistress of Richard for a while when Jeff, an engaging but but unrepentant dreamer, falls madly in love with her. Marceline first turns him down but finally accepts him after she breaks up with Richard. But the coquette has not given up her escapades to which the young florist, nicknamed "Jean de la Lune" for his naivety, turns a blind eye. Little time after their wedding , Marceline becomes infatuated with the good looks of a superficial young man, Alexandre. But Jeff, who has developed a fondness for Jean, intervenes to save the couple.