It’s characteristic of Erick Zonca’s extraordinary first feature, The Dreamlife of Angels, that we never learn how Isa got that scar across her right eyebrow. It’s just there: a fragment of personal history, borne in the flesh by someone who doesn’t think much about her past.

Barely into her 20s, Isa clomps onto the screen sporting a brush haircut that was surely self-administered and wearing the motley layers of a wanderer. Her clothes, like her eyebrow, must have a history (or histories–these wrappings may have belonged to three or four different people before Isa put them on), but she carries her outfit comfortably, as if she weren’t living in it as a transient.

We soon learn that Isa has traveled to the northeast of France in much the same spirit. She’s arrived expecting to stay with a friend. But she can’t have kept in touch with him; he’s long since moved on from the trailer where he slept. The neighbors have no forwarding address; in fact–no surprise–they scarcely know his name. But Isa doesn’t worry, despite this transition from borrowed shelter to none. Having made her way to the provincial capital of Lille, bundled up against the snow, she now simply camps out.

By now, only five minutes have passed in The Dreamlife of Angels. Already we know that this dark young woman, with her oval face and ripely assertive mouth, is as rootless as a person can be. And yet, miraculously, she’s fully a person. Isa (Elodie Bouchez) comes onto the screen intact–as complete as if the filmmakers had found her, instead of making her up.

The Dreamlife of Angels is the story of one season of Isa’s vagabondage and of the lives she inhabits while slowly passing through Lille. Spending time in a city that’s not her own, squatting in the apartment of someone she’s never met, Isa adds her plenitude to two other characters, who in their different ways give her a void to fill. One of them, a teenager named Sandrine, lies in the hospital in a coma, the victim of a car wreck. Isa not only reads the diary Sandrine has left behind but also inserts herself into it, as if carrying forward the girl’s interrupted life. The other character, Marie (Natacha Régnier), can still walk, talk, smoke cigarettes and swill wine, yet in her own way, she turns out to be as present-but-absent as Sandrine.

At first, though, Marie seems to be the assertive and capable one, compared with Isa. The two meet at a small factory, where Isa has found a minimum-wage job sewing the sleeves for blouses–a job she loses as quickly as it was found, since she stitches her whole first batch inside out. But before getting the boot, Isa has experiences that are denied to most characters in movies today. She performs manual labor, receiving an apprenticeship whose roughness will be recognized by anyone who’s done the same. She falls in with the other women, who share their lunches with her and otherwise offer the brusque yet easy welcome that’s common on shop floors, though unknown amid the computerized cubicles you usually see onscreen. Most important, Isa retreats into the refuge of working women, the toilet, where she has her first encounter with Marie.

Bonier than Isa, more conventionally pretty but so pale that she looks translucent, Marie is your basic 20-year-old enragée. When she meets a luxury car, her first response is to kick in its taillights. So when the new girl follows Marie “home” from the factory–that is, to the apartment where she’s been squatting–Isa temporarily seems like a mouse, and Marie like the skinny lion who wants a thorn in its paw. It’s Marie who provides shelter and Marie who shows Isa around town. But when the new friends try to get into a concert without paying, you notice that Isa does all the talking. Marie hangs back. Her mane, you see, is limp, and so is her rebellion.

The rest of the film might be described as the playing out of a double obsession. Marie, who can be so forceful against a fancy car, goes supine when confronted with its owner, a sleek-haired rich boy named Chriss (Grégoire Colin). Suddenly, all her ferocity pours into the fantasy that Mr. Money might make her his girlfriend. Isa, meanwhile, sets off on a different avenue of escape. Having learned that the rightful owner of her squat lies in a hospital, unconscious and unvisited, Isa begins spending time at her bedside. On one level, she’s caring for Sandrine, making her recovery slightly more likely. On a second level, she’s behaving like Marie: disappearing into the imagined life of someone with property. And then, on yet another level, Isa is circling back to her own reality, as Marie refuses to do. Sandrine’s diary shows that her life, despite the property, hasn’t been all that great.

What do I like best in this story? The air currents. Zonca films all this with such immediacy–and his two astonishing actresses perform in it with such self-abandonment–that you can smell the cigarettes and unchanged sheets in their apartment, and catch the chill of the breezes that ripple through Lille’s streets. There’s a sense of space–real, open space–in every scene. Maybe that’s why Isa and Marie, though so unalterable in character, never seem predictable as they develop throughout the film. They have room to unfold.

They even have room for silliness. In one inspired sequence, Zonca sends the two friends to search for jobs at a new theme bar called The Hollywood. The waitresses there will impersonate American film stars, so Isa and Marie can’t simply apply for work; they have to audition. Of course, the scene is a gift to the actresses: Bouchez and Régnier get to perform as Isa and Marie performing as Madonna and Lauren Bacall. But even within this diversion, fresh revelations come whistling through the picture. Asked to demonstrate how their characters would “act,” Bouchez and Régnier push themselves to the point of caricature. They show us an irrepressible, outgoing Isa, who bounces nuttily onstage next to a withdrawn, narcissistic Marie, who can scarcely bring herself to look up and speak. And Zonca, as usual, lets the actresses work. He keeps the camera back just far enough so that he doesn’t crowd them; he lets the take continue just long enough so that he doesn’t force anything. Moments of pure artifice don’t get more natural than this.

There is, toward the end, another moment, brief and unforgettable, when the film’s sense of open air becomes awful. Of course: Isa and Marie can’t float forever in their fantasies of other lives. But that’s a measure of the integrity of The Dreamlife of Angels. While the characters are blowing around loose, the ground remains at their feet. Anyone who’s been on the scuffle at 19 or 20 will recall that feeling, with a mingled smile and shudder.

And for Erick Zonca, The Dreamlife of Angels must be such a recollection. Although the picture seems absolutely contemporary, Zonca is in his early 40s. Surely his own wandering years, or those of people he knew, have figured into the atmosphere. You might even say that his self-projection into Isa and Marie is the film’s ultimate case of living through others. In The Dreamlife of Angels, a middle-aged man fantasizes himself into two young women. That he does so almost invisibly, with the ease of breathing, is part of what makes his film a revelation.

What’s revealed is that impossible thing, the truth. Reviewers ought to tremble when they write the word; filmmakers themselves don’t dare mention it. In fact, I have before me an interview with Zonca in which he claims to want to make “tragic, violent, moving stories that have nothing to do with real life.” Tragic, violent, moving–all right. But “nothing to do with real life”? That’s the one lie he’s told so far.

Screening Schedule: If you’ve got a free Saturday afternoon in March or April and are in the neighborhood, drop by the Brooklyn Museum of Art for the series East Side Stories: Coming of Age Behind the Wall. You’ll have your pick of seven films, made between 1989 and 1997, all of them about being young in the Eastern bloc, both before and after Communism. Full information on the series (which runs March 6 through April 17) may be had by phoning (718) 638-5000, ext. 230.

And even though this part of it is unofficial, take it from me: You’ll score extra points for coolness if you show up carrying a copy of The Red Atlantis (Temple), J. Hoberman’s new book about Communist culture in a post-Communist world.