Based on

Movies like Règlements de compte (1963)

Bryant, an American, arrives at the Gare de Lyon after serving a sentence of hard labor at the Baumettes prison for stealing gems (which, incidentally, have not been found). He was immediately spotted and followed by individuals with knowledge of his past activities. One of them, in particular, pursues him mercilessly and, after a series of twists and turns, kills him, without ever finding the treasure.