Cherchez l'idole (1964)

Cherchez L'idole tells the story of a man pushed into stealing a jewel by his selfish girlfriend. After stealing the jewel, he hides it in a guitar while being chased. He then has a change of heart, dumps his girlfriend and decides to return the jewel. Only now he has to find the guitar he hid the jewel in, which is in the possession of one of five musicians.