Justin, a lyricist by trade, and his friend Pierre, a composer, lead a bohemian life in Paris. Justin thinks his mother Josefa is richer than she appears, and decides to swindle her out of three million centimes by using Pierre as an intermediary in a case involving an insolvent check. Josefa uncovers the ruse and refuses to help her son. However, Pierre has discovered the identity of his friend's father, who had been unknown to him for twenty years. With the help of Justin's mother, the two friends do everything they can to extort the son's missing three million centimes from his ashamed and repentant father.

Joséfa Trucullia vit dans le centre de la France. Elle tient une épicerie et un café. Elle est respectée et très riche. Son fils, Justin, habite à Paris et écrit des chansons. Il n'a presque pas de ressources mais sa mère est avare. Justin charge son meilleur ami, Pierre Corneille, d'aller escroquer sa propre mère d'une somme importante afin de l'aider dans sa carrière...

Un'ostessa tanto avara quanto povera rifiuta di prestare al figlio - che invece la crede ricca come tutti i paesani - una certa somma. Un'amica del ragazzo, scoperto che il sindaco è suo padre, riesce a farsi dare da lui il denaro necessario a lanciare le canzoni che hanno scritto assieme.