The theater of corporate backstabbing reaches a new extreme of clandestine malevolence in Olivier Assayas' French cyber-porno-office thriller Demonlover. Early on, the brusque, mannequinlike, yet eerily vulnerable Diane (Connie Nielsen, from ''Gladiator'') goes on a business trip with Hervé (Charles Berling), her shaven-headed, beady-eyed fellow suit, who's a deadpan expert at playing rivals off each other in order to make himself look trustworthy. The two arrive in Tokyo to negotiate a deal with TokyoAnimé, the world's leading creator of erotic cartoons. As they tour the city's bubbly but sinister nightlife (automaton go-go girls, etc.), then watch a sample of the kind of animated spectacle that they're considering distributing (think ''Spirited Away'' with a cast of naked, writhing Lolitas), Assayas' arresting theme comes to the surface: In an age when corporations are in the business of engulfing underground culture, the amoral, even violent, spirit of the product will seep up into the company.
For an hour or so, ''Demonlover'' is an entrancingly devious soap opera of executive decadence. When Gina Gershon shows up, playing an American entrepreneur who may or may not be linked to a website that features forbidden sexual torture, her hostile lubriciousness only thickens the atmosphere of cutthroat desire. No doubt about it: Assayas is a major talent. He also, unfortunately, has major pretensions. Taking his cue from the David Lynch of ''Lost Highway'' and ''Mulholland Drive,'' Assayas can't resist turning ''Demonlover'' into an overcalculatedly irrational rabbit-hole-to-the-dark-side thriller. The movie morphs into a ''dream,'' all right, but I confess that all I wanted to do was wake up from it and return to the slithery intrigue of corporate depravity.