Marion Cotillard's Stellar Turn in 'Rust and Bone'

I liked being watched. I liked turning guys on. Getting them worked up. But then I'd get bored.

Such is the modus vivendi of Stéphanie, a callous temptress played by Marion Cotillard in the new French drama Rust and Bone. An orca trainer by day, she is forced to confront her self-destructive nature after losing both legs from the knees down in a tragic on-the-job accident. Eventually she finds comfort in Ali (Matthias Schoenaerts), a street-fighting single father who thrusts her out of the darkness and into the light. The film is directed by French auteur Jacques Audiard, and loosely adapted from a collection of short stories by Canadian author Craig Davidson.

"I didn't have time to shoot this movie, but it was irresistible," says Cotillard on a recent fall morning in New York. "We went for it and jumped into the unknown, and I'm glad we did."

Cotillard's packed dance card shouldn't come as a surprise. Since winning an Oscar in 2008 for her portrayal of the singer Édith Piaf in La Vie en Rose (and becoming the first Best Actress winner for a French-language turn), the Gallic performer has transformed into a bona fide Hollywood star, with roles as an alluring flapper in Woody Allen's Midnight in Paris, and as a femme fatale in Inception and The Dark Knight Rises, both directed by Christopher Nolan. She's also been the face of Lady Dior since 2009.

After wrapping the final Batman film, which Nolan delayed shooting in order for Cotillard to have her baby, she had just one week to prepare to play Stéphanie. With her 5-month-old boy, Marcel, in tow, she hopped on a plane to the Côte d'Azur to tackle her most physically demanding role to date—one that required her to fold her legs back during wheelchair scenes and to don green tights in other scenes so her legs could be removed with CGI. The result is one of the truly great special-effects triumphs of the year. The legless sex scenes—and there are quite a few—were especially difficult to film.

"Usually I don't like to do love scenes but sexuality is a very important part of the movie," says Cotillard. "When we did the scenes, I was a hundred percent in character, but a part of me was also very happy about what was happening to her."

She adds: "But we also had a lot of fun. Jacques was like, 'Cut! Your leg is making a shadow on Matthias's back, so we won't be able to use it. Put your leg higher!' That was really funny."

And the gamble seems to have paid off. Audiard's gritty, expressionistic tale, an affirmation of the Pat Benatar maxim "love is a battlefield," is earning Cotillard major buzz this Oscar season. An ethereal beauty—and living proof that the eyes are the windows to the soul—Cotillard says she related to Stéphanie's melancholia.

"I was a very special kid," she says. "I had questions like, 'What am I here for?' and because I didn't have any answers, I struggled with my soul. I had a very hard time sharing things with people because I was very shy and didn't really understand how relationships worked. When I started to understand that what we share creates an energy to the world, I started to relax and spend time with people instead of avoiding them."

Raised in Beaucé, a town near Rennes in northern France, Cotillard says she was surrounded by "storytellers and passionate people." Her father served as a theater director and mime, and her mother was an actress. She made her onstage debut alongside her mother in a play directed by Daniel Mesguich. And when Cotillard wasn't acting, she was watching movies.

"All my big, big shocks as a kid watching movies came from American movies," she says. "I grew up with musicals like Singin' in the Rain and Victor Victoria, and of course, Jaws. We watched Jaws like 50 times." She laughs. "I had no idea that I would have the opportunity to work here. It makes me very happy."

The 37-year-old actress has come a long way since making her Hollywood debut playing a Newsweek photographer in Tim Burton's fantasy epic Big Fish. Like The Dark Knight Rises, Rust and Bone addresses the growing divide between the haves and the have-nots, an issue Cotillard is very passionate about.

"I will always be upset about the fact that we care less about humanity than about how to make industry work," she says. "And, even though we fail in a lot of places, we still continue to think that we need to keep the money world healthy, and that's how we're going to make it work. But I don't think it's working. Why would we continue to feed the machine when people are starving?"

In her limited free time, Cotillard listens to a variety of music, ranging from Otis Redding and Nina Simone to Radiohead and Adele. Two years ago, she toured with the French band Yodelice, and hopes to return to music again soon. For now, however, she's occupied with her baby boy, whose father is her boyfriend, actor and filmmaker Guillaume Canet.

"It's like you have a different mission," she says of motherhood. "I've always tried to stay away from the bullshit, but now the no-bullshit approach works. Suddenly this piece of authenticity arrives in your life, and it's a revelation about how you deal with yourself because you're not the most important person anymore."

But this new phase in her life has had positive repercussions on her career as well. "I was so tired from being on no sleep making Rust and Bone," she says, "but at the same time I had this huge energy that I'd never experienced before brought by what happened in my life."