“I know I look like a witch.” “You’re foxy, and you know it.” The exchange comes from the cerebral sci-fi terrorscape of French auteur Claire Denis. In Denis’s latest feature, High Life, the “witchy” Dr. Dibs (Juliette Binoche), stationed on a spaceship, lusts over fellow shipmate Monte (Robert Pattinson, strapping with a buzz cut). The two are trapped in a dystopian future in which death-row prisoners are “spared” by participating in an experimental space program. Raven tresses cascading down her back, the 55-year-old Binoche wears a tight white lab coat zipped to reveal her cleavage. Dibs’s efforts to create human life that can withstand radiation is punctuated by visits to the “fuckbox” to get off on what appears to be a vaulting horse horned with a metal dildo. In the film’s most ecstatic — and certainly memorable — scene, Binoche bares all in a sweaty trance that makes bachelorette-party mechanical bull-riding look like a Disney attraction.

Galaxies from the doe-eyed ingenue who flounced through The Unbearable Lightness of Being in 1986, this Binoche is no less feminine, or sexual, for her five-plus decades. And she is just as sympathetic — even when plotting to surreptitiously inseminate her patients. It is the actor’s intense emotions, whether conveyed through a soft grin or doleful gaze, that grants a sense of vulnerability to even the most formidable female characters. Binoche straddles, stuns, and smirks at the world, but her tears are no less plausible, her sadness no less real.

From spacecraft seduction to Mallarmé jokes over tumblers of whiskey, Binoche seems at first to offer an entirely different woman in Olivier Assayas’s Non-Fiction. As Selena, she plays a classically trained actress best known for her role as a “crisis management expert” in the shoot-em-up cop show Collusion. Guillaume Canet plays Selena’s caddish husband Alain, the fox of the Parisian publishing world. A sensuous Luddite who laments the decline of the printed page, Selena plays cheerful hostess to Alain’s cohort only to exclaim “Merde!” (“Shit!”) at a blogger with whom she disagrees. Where Dr. Dibs is chilly as a petri dish, Selena is bright and earthy — but both rule their films as temptresses equally tender and intimidating.

Teetering between rompy farce and scathing critique, Non-Fiction is like a sobered version of Jean Renoir’s Rules of the Game (1939) for the French literati. Alain is cheating on Selena and Selena is cheating on Alain. But even in this “vacuum-sealed” dramedy of manners, Binoche beats as its earnest heart. “He doesn’t love me less. Maybe more,” she says of Alain’s infidelity to a pal during a break in shooting. “He feels guilty, knows he may lose me. It scares him, brings him closer.”

The first time Binoche gets naked this time around, the partner in question is unseen for 30 seconds of shadowed sheet contorting. He is revealed to be the schlubby, sensuous Leonard (Vincent Macaigne), an author formerly represented by her husband’s press. “I hate his view of women,” Alain shares with Selena, not realizing that the movie-house blow-job scene in Leonard’s novel is based on a liaison with his wife. “Embarassing for her, no?” Brewing a pot of tea in their quiet kitchen, Selena doesn’t bat an eye as she responds, “Maybe she likes it?”

As in Non-Fiction and her sultry turn in Denis’s last film, the comparably breezy anti-rom com Let the Sunshine In, Binoche is best in High Life when she is suddenly sympathetic. “All of you are petty criminals,” Dr. Dibs scoffs at her human lab rats halfway through the film, a few scenes later welling up with tears as she concedes her crime to a prisoner who has suffered a massive stroke. “Everything will be okay,” she tells him mid-massage, as though also assuring herself. The line between compassion and foreplay sufficiently blurred, Dibs calls dibs on her patient’s forearm, bestowing a swift IV euthanasia.

When confronting Leonard toward the end of Non-Fiction, Binoche summons a similarly decisive demeanor. “You don’t answer my messages,” he says at the bar where she’s ordered a double espresso and orange juice. “No,” she responds, steady-gazed. “It’s not a matter of time. It’s a matter of fatigue.” “You’re trying to say it’s over,” Leonard avers. “I think I’m doing more than trying,” she says. “It’s a done thing … I have no time to talk it out.”

And right when she seems to be executing the coldest breakup ever, her hand starts to shake and she gasps for breath, requesting that he not turn their affair into another book. “I’d never forgive you,” she says, blinking back tears. “I’d destroy you. Your life will be hell.” Somehow, it’s easy to believe that.

Non-Fiction by Olivier Assayas and High Life by Claire Denis are currently screening nationwide.