" A Woman at Her Window," an exquisitely lackluster title, may be recommended as a daffy indulgence to art-house customers who want to go out afterwards and try to make sense of the awesomely convoluted and ridiculous plot. It will help, naturally, if you don't mind paying first-run prices for an evening or rare expository bewilderment.

Supposedly working from a novel by Pierre Drieu La Rochelle, best known for "Le Feu Follet," which Louis Malle filmed back in the early '60s, Jorge Semprun has constructed a scenario that can serve as a monument to confusion, a veritable colossus of inept trickiness. Semprun's basic trick is playing around with the time sequence. Beginning the narrative on a note of "Didn't we meet at Marienbad?"obscurity, about three weeks after the event that sets the story in motion, Semprun commits himself to interminable flashing back and catching up.

This deliberately scrambled continuity simply makes a hash of the plot. Semprun, abetted by director Pierre Granier-Deferre, who thinks he's evoking bygone decadent glamor by imposing a ponderously glossy style, is so determined to be a tease that it seems to take an eternity for the characters to arrive at essential dramatic encounters. Even then the material is controlled by evasion rather than illumination. Clumsy or missing transitions obscure the time sequence. Obligatory scenes are nowhere to be found. The continuity takes a 10-year jump after failing to sort out the events of three weeks.

A whole new movie, epic in scope, could be written based on the presumably crucial, action-packed episodes in the lives of the major characters that are never depicted, only reported or alluded to secondhand.

The expository camouflage may have grown out of the need to conceal the romantic-ideological shallowness of the underlying love story, in which a spoiled, frivolous, adulterous society woman, played by Romy Schneider, is redeemed by falling in love with a fugitive communist agent, played by Victor Lanoux.

The title refers to their fateful first meeting, which occurs in Athens on the tendentiously chosen day of Aug. 4, 1936, when Gen. Metaxas announced a military take-over of the government. Schneider opens the shutters on her ground-floor hotel suite for a breach of air and discovers Lanoux fleeing from the roundup of known or suspected Reds. By letting him in, she supposedly ennobles her life, committing herself to A Great Romance and A Great Cause in one convenient package.

Shamelessly kitschy to begin with, the premise looks even sillier after Semprun and Granier-Deferre get through trifling with it. Like the heroine, the filmmakers make an absurd spectacle of themselves trying to have their cake and eat it.

The combination of palpitating sex fantasy and nostalgic, self-congratulatory left-wing virtue is amusingly preposterous, but the filmmakers aren't consciously kidding. Perhaps they imagined that this nonsense would buffalo fashionable women still susceptible to the fiction that professed radicals make the best lovers. You see that guy, they seem to be saying when Lanoux is on the screen, he's us too! By the same token, the pampered heroine and another rich glamorous playgirl embodied by the delectable, tawny-haired Delia Boccardo seem to expose the filmmakers' secret desires: We'll take one of those and one of those and don't forget your check-books!

The movie has an abundance of strictly superficial, stupefying or sarcasm-inducing entertainment value. Romy Schneider, for example, is an irresistible hoot pretending to be awakened by a revolutionary Prince Charming while promenading and lounging about in an ostentatious array of vintage gowns, autos and headgear. Her chest heaving in erotic anticipation prior to one rendezvous, she suggests a cartoon illustration for the lyric in "Night and Day" that begins, "Like the beat, beat, beat of the tomtom...."

Semprun's idea of a Big Irony is to conclude the sprawling, mystifying plot with an epilogue in which Schneider reappears as the love child of the socialite and the revolutionary. Her existence is difficult to credit, but she supposedly happens to be in Athens on the very day the Junta takes over, April 21, 1967, as I recall. History repeating itself, as it were. On the contrary, it's only a disorganized scenario writer figuratively biting himself in the rear after spending tow pointless hours chasing his tail.