Sins of Paris (1953)

Madeleine Lebeau, a woman who charges for her easy virtue, has a plan that has some of her customers paying more than others; she tells them she is pregnant and, to avoid complications, the men pay her money and don't hang around for the birth. Yves Furet, a shiftless gambler, who not only encourages her in her business ventures but is also her fiancée, shares the fruit of her non-labor. She latches onto a wealthy widower, Henri Vilbert, who throws her a curve-ball when, after she tells him she is pregnant, he is overjoyed as he has fallen in love with her and is looking forward to becoming a father. She plays along for a while, but becomes ashamed when she sees how Vilbert is devoting his whole life to a child that she isn't carrying. She fakes a miscarriage and his kindness makes her feel guilty and she confesses, but he doesn't believe her. So she tries another plan.