THE ESSENTIAL elements of television sitcoms have remained unchanged since their invention: A tidy, long-standing domestic situation is threatened with change, but inevitably reverts to its original order by the end of the show -- primed to be upset again next week. It's an almost baroque image of stasis, a constantly spinning wheel that never moves forward. That is precisely the image that Françoise Ozon explodes in his hilarious debut feature, Sitcom.

Ozon doesn't waste any time about it, either. The opening scene shows a bourgeois businessman returning to his palatial home. From outside we hear chipper greetings, a round of "Happy Birthday," then gunshots and shrieks of horror. What led to such nightmarish violence? To answer, the film flashes back to an earlier homecoming by the father, this time bringing a new pet for the family: a white lab rat. As the animal sniffs about in its cage, each member of the household, in turn, stares into its large pink eyes and decides then and there to change his or her life completely. The son announces over dinner he's gay. The daughter cripples herself by throwing herself out a window; from her wheelchair, she orders her boyfriend about in a series of S&M games. The mother, desperate and confused, seeks help from a therapist. Even the maid takes to lounging around, seducing whoever she can.

It doesn't take a master's in film history to see the influence of Buñuel here. One extended gag -- with all manner of strangers heading up to the son's bedroom for some "games" -- is so good, I'm sure the Spanish master would have roared laughing, all the while wondering why he hadn't thought of it first.

Ozon has made a good move latching onto Buñuel, who understood more than any other director how the most deadly serious matters are best handled with a light, playful attitude. Unlike Ozon's previous shorts, which for all their brilliance felt hollow and calculating (unavoidable when you use shock for shock's sake), Sitcom entertains even as it rips every standard of decency to shreds. It even has the good sense to turn on itself, confessing at the end that it's absurd to blame the problems of a family this messed up on a harmless little rat.