The Flower of Evil original title La fleur du mal is a 2003 French film by Claude Chabrol.
In a grand house at Bordeaux lives Grard, owner of a pharmaceutical business. A drinker and fornicator, he disgusts his son Franois, recently returned from the USA. To Grards disgust, his second wife Anne is a candidate in the municipal election.Her daughter by her first marriage, Michle, is excited by the return of Franois and the two go off for a weekend at Pyla, where they become lovers. Annes old aunt Line encourages the pair. ........
Source: Wikipedia