A nightclub gadfly (Guillame Canet) sneaks into a private party by claiming to know a guy named "Jordan". The host catches him and enlists his aid in finding this guy "Jordan", which he agrees to for some reason. After a series of misadventures that take up nearly half the movie he finds "Jordan" and his sexy sister "Violaine" (Asia Argento), and they turn out to be some kind of vampires. They have been making these kind of erotic vampire movies both in Europe and the US for forty years now, and they're really getting to be kind of old hat. This one is also kind of annoying in that it is very modern-day French (i.e. very glossy and derivative of Hollywood). Jean Rollin was doing this much better thirty or forty years ago.
It does have a couple of good points though. Asia Argento is absolutely smokin'-ass hot. She has a very memorable scene where she picks the protagonist up in a club and takes him home. She goes to fix him a drink, which she drugs, and comes back naked from the waist down (her pants mysteriously MIA). Moments later they're in bed where in his drugged state he hallucinates that she is THREE bottomless vampire girls all sucking on him (and not just in the vampiric sense!). The guy also has a wife(?) who is a lounge club singer. At one point she sings what appears to be a French lounge-club version of the great Willie Nelson song "The Night Life" (i.e. "The night life ain't no good life"/"But it's my life"). I'm not sure this is actually the Willie Nelson song, since it's in French, but if not, he should probably sue.
But if I sound a little uncertain of some things, it's because I didn't really understand French dialogue very well, but perhaps I should have tried more because the English subtitles were either generated by a malfunctioning computer translation program or written by someone who had no grasp on the English language. They're often unintentionally funny (such as when they try to translate bizarre French idioms directly into English), but mostly they're just distracting. I don't know if all of this adds up to a recommendation or a pan, but you can decide for yourself I guess.