"Put yourself in my place." It's a line heard a number of times in "Two Days, One Night," the exquisitely simple and moving new film from Belgium's Dardenne brothers.

It's central to the story, but doesn't the line also encapsulate what cinema is supposed to accomplish, essentially? Forcing us to put ourselves in the place of those onscreen and to wonder, often with discomfort: What would I do?

Not all filmmakers pull it off, but it's something the Dardennes, Jean-Pierre and Luc, are remarkably good at — making us understand just what we share with their characters, working-class people in industrial Belgian cities who are decidedly neither heroes nor villains, just ordinary folk trying to get by.

And their effort is even more remarkable here, because the writer-directors are working for the first time with a bona fide, glamorous movie star: Marion Cotillard. The fact that it works so well is a tribute both to Cotillard's committed, selfless work and to the Dardennes' unerringly authentic instincts.

Cotillard plays Sandra, a mother of two young children who works at a solar panel factory. It's significant that we never see Sandra actually doing her work. It doesn't matter. Over the course of the film we'll learn just how important that work is — not simply to her economic survival, but to her very identity and sense of place in the world.

The action unfolds at a deliberate pace. Only gradually do we realize Sandra has been on a medical leave for depression. As the film begins, we know only that she's been hit with a severe blow: The boss has determined that 16 workers can perform the job of 17, with a little overtime. Her fellow workers have been given a choice — a 1,000-euro bonus ($1,200), or Sandra's return. They've voted for the money.

But Sandra wins a second chance: A new ballot, on Monday morning. All she has to do is convince a majority of the 16 to give up their bonus. She has, as the title says, two days and one night.

With the help of a concerned and supportive husband (Fabrizio Rongione), Sandra heads out to knock on doors. Each of these encounters is painful. Sandra is a mass of jangled nerves, prone to popping Xanax to get through the day, or escaping to bed in the afternoon. She hardly feels capable of arguing for her economic survival.

The Dardennes don't make it easy for her, and they don't make it easy for us. No shortcuts are taken. We hear Sandra speak the same excruciating lines, plead the same case, again and again. This mundane repetition — rare in the movies — is just one aspect of the Dardennes' filmmaking that gives it such a powerfully naturalistic feel.

Cotillard is hugely effective at conveying this elemental struggle — not just for her job, but for her sense of self-worth, and, not to overstate it, for her life. With no makeup, a messy ponytail and a uniform of jeans and tank tops revealing colorful bra straps, Cotillard is stripped of glamour. But her struggle is also reflected in her eyes — at times empty and glassy, at others steely and determined. And even in her gait. Watch her trudge reluctantly toward another difficult doorstep encounter. Her body seems weighted down by dread.

The finale is redemptive, yes, but not in the way you expect. Not surprisingly, it's the most un-Hollywood of endings. As we watch Sandra trek off down yet another urban pathway, growing smaller as the world grows bigger, we're struck in a very visual sense how her story is just one of many, equally powerful ones — in her town, in her country, in the world at large. Few filmmakers drive this universality home as well as the Dardennes.

"Two Days, One Night," an IFC Films release, is rated PG-13 by the Motion Picture Association of America "for some mature thematic elements." Running time: 95 minutes. Three and a half stars out of four.

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MPAA definition of PG-13: Parents strongly cautioned. Some material may be inappropriate for children under 13.