Debout les crabes, la mer monte! (1983)

Behind bars for five years, Marthe, a prostitute, is furious at having been locked up for a crime she did not commit. Finally freed, the young woman decides to take revenge and find the real culprit, her pimp. But on the way to Nantes, on a train, Marthe is troubled by Louis Paimboeuf, a charming history teacher.