One to Another (2006)

Directed by Jean-Marc Barr

A story about bunch of people who live in a town in provincial France. At the center of it all is Pierre, a conceited and vain bisexual musician in his late teens who acts as a magnet, to varying degrees, for a whole array of characters - from his sister Lucie, with whom he has a heated incestuous relationship, to a city councilor with whom he participates in gay orgies. When Pierre turns up dead, Lucie investigates the reasons for his demise and charts the network of sadomasochistic relationships that crisscross the town.