Merci Docteur Rey (2004)

Thomas Beaumont is recruited into an illicit love triangle to watch a much older man's sexual liaison, but ends up witnessing what turns out to be his murder. The next day Thomas' opera diva mother informs him that his long lost father has been in Paris--until the previous night when he was murdered. Realizing it was the murder he witnessed, Thomas is now thrust into a maelstrom of off-the-wall encounters and mistaken identities, including an eccentric actress who has come totally unhinged by the death of her psychiatrist, the infamous Docteur Rey.