A shy, penniless employee of the garage owner Grillot, the gentle Louis wins $10 million in the lottery. Flitting along the banks of the Seine, he takes in Raoul Grandvivier, an unknown, untalented painter who has just botched a spectacular suicide intended to draw attention to himself. Raoul takes him back to his studio, where he meets his charming daughter Lucie. In order to see Lucie again, with whom he is in love, Louis offers to sell the paintings. In reality, he's the one paying for them, to make it look like a wealthy art lover.

Un homme timide et sans le sou voit sa vie bouleversée lorsqu'il gagne à la loterie. Amoureux de la fille d'un peintre, il va se faire passer pour l'intermédiaire d'un richissime amateur d'art...