La Demoiselle d'Honneur [2004]

In Lille, hairdresser Christine has raised her son and two daughters alone. Philippe Tardieu, who works in a renovation company; Sophie Tardieu, who is going to marry Jacky in a couple of days; and Patricia Tardieu, who seems to be using drugs, live with their mother in a middle-class house where Christine works. Now, while a teenager is vanished in the city, Christine invites her son and daughters to meet her boyfriend, the wealthy Gerard Courtois who has just divorced and is selling his house. She gives her garden stone head of the goddess of flowers Flora that Philippe adores to Gerard who tells her that he is leaving on a business trip to Italy the next day, but he disappears from Christine's life. At Sophie's wedding, Philippe meets her sexy bridesmaid and Jacky's cousin Stephanie "Senta" Bellange and they have a one-night stand. Despite the unstable and apparently imaginative Senta's odd behavior, Philippe falls in love with her and suggests four weird things to prove their love: planting a tree; writing a poem; having homosexual intercourse; and killing a person. When a homeless beggar is found murdered in the harbor, Philippe decides to fantasize that he had murdered the man to prove his love to Senta. When he wakes up the next morning, Senta tells him she murdered Gerard to please Philippe and describes her crime in detail. Philippe decides to visit Gerard to find the truth about Senta.