The Disenchanted (1990)

Seventeen-year-old Beth is just finishing school, and lives in Paris with her bedridden mother and younger brother. She is annoyed because her boyfriend suggested she try sleeping with other men - the uglier the better. Sugardad, a doctor who visits her mother, and supports them with occasional cheques, now has his eyes on Beth. Alphonse, an older man, intervenes when Beth's boyfriend is fighting with her on the banks of the Seine. When she visits Alphonse later, they end up discussing poetry.