Juliette Binoche moves through the French drama “Who You Think I Am” as if possessed. From moment to moment, her character — an academic with a turbulent inner life — looks tense or wildly happy. Emotion, by turns, lightens and darkens her translucent face, and changes her body, gait and gestures. She laughs, she cries, expands, contracts. At times, she all but floats down the street, buoyed by the love of a younger man. Then again, she may be less high on him, per se, than on how he makes her feel.

Filmmakers can get a lot of mileage just by filling the screen with Binoche’s face, which is often a movie’s greatest special effect. It’s a lovely face, eternally so, yet while beauty tends to pull us in, it doesn’t necessarily hold and bewitch us, keeping us hooked. But Binoche is a virtuoso of sentiment, with a mesmerizing control of her face. She can soften, harden or crumple it into blotchy fragments, and then effortlessly piece it back together, with or without ragged seams. And while she’s a great weeper, more impressive is how these inundations, these eddies of feeling, move under her skin.

You get to know Binoche’s character, Claire, through the modern-era version of the confessional box, a.k.a. a shrink’s office. She’s a mess, and a guy is to blame, or so it seems. What transpires proves more complex or at least complicated. There are two guys, Claire tells her new therapist (Nicole Garcia), both perfectly coifed and readily undressed. When the first (Guillaume Gouix), dumped her, Claire reveals, she turned to the modern-era version of the devil, a.k.a. social media, to spy on him. With a seductive photo and a fake identity, Claire transformed into the much younger Clara, sneaking into his life and then into that of the conveniently situated lover No. 2 (François Civil).

There are twists and turns, some obvious, others preposterous. Characters come and go (Charles Berling pops in too briefly as Claire’s ex-husband), and time slips away as Claire giggles, glows, musses her hair and loses her bearings. Throughout, there are gestures toward larger issues, including desire, beauty, gender and age. There’s a lot of talking, some dancing and more talking, this being a French movie. In one funny, pointed scene, Claire drives in circles frantically talking to a lover on her cell while her puzzled, exasperated sons watch, waiting to be picked up. Binoche seems to be having a good time, but her character could have benefited from fewer tears and histrionics.