Les dames du Bois de Boulogne (1945)

Realizing that her lover (Jean) is losing interest in her, a society lady (Hélène) gets revenge by tricking him into marrying a former prostitute (Agnès). After the wedding Helene tells a stunned Jean about his wife's secret past, but the ending has more than one surprise twist. This is a modernized but fairly faithful adaptation of the story of Madame de La Pommeraye from Denis Diderot's novel Jacques le Fataliste.