Four Days in Paris (1955)

Mario, a star ladies' hairdresser, has Nicolas as a friend and Gisèle as his mistress, who is coveted by Nicolas. To boost the salon's finances, Nicolas takes advantage of a billionaire, Madame Alvarez, by selling her a pseudo-rejuvenation serum invented by Mario. Mario suddenly falls in love with a provincial girl, Gabrielle, and pursues her to the South of France, where everyone meets up to finish the film in song.