Chouchou leads a happy life between his comrades and his fiancée. But his father wants him to marry a rich American in love with him. Chouchou refuses and looks for work in order to be independent and to marry the one he loves.

An accordionist playing in disreputable halls is mistaken for a gangster by a special envoy from the American crime syndicate in charge of investigating the French milieu. The American will prepare a hold-up with a gang of women specialized in scamming tourists. But the accordionist will make the hold-up fail and all the criminals will end up behind bars.