Dédé de Montmartre, former king of the accordion, has become a bad boy who lives off drug trafficking and prostitution. He sets his sights on a young girl, fresh and naive, Odette, saleswoman at Galeries Lafayette. But he is touched by the charm of this midinette.
The workers Legendre and Martinet have won a large sum in the national lottery. Instead of squandering it, they had the good idea to invest it in industry. Happy in business, they soon find themselves at the head of a fortune. But their characters are very different. Legendre, who is brave and honest, narrowly escapes the malevolence of a couple of harlots. Martinet, his former work companion, has become a crooked and formidable financier. Both will face each other in court, the honesty of the first finally triumphing over the greed of the second.