The influence of the Dardenne brothers is obvious in Jacques Audiard’s unconventional romance, shot in a gritty style to reflect lower-class environs and tough economic times but perhaps also to conceal the fact that in terms of plot it has many of the attributes of a old-fashioned tearjerker. In many respects the Dardennes employ the tropes of soap opera too, but in their hands the devices are scrubbed clean of cheap sentimentality and ham-fisted emotional appeals. Audiard, at least on the evidence of “Rust and Bone,” doesn’t possess equal skill; it’s too obvious and manipulative by half.

Matthias Schoenaerts plays Ali, down-on-his-luck pugilist who shows up in Antibes with his five-year old son Sam (Armand Verdure), whom he’s taken responsibility for after his ex had used the lad in a smuggling scheme. Jobless, Ali moves in with his sister (Celice Sallette), who works at check-out in a grocery, and her genial truck-driver lover. To make ends meet, he links up with a sleazy fellow who arranges bouts for him in bare-knuckle street fights, and who also takes him on as an assistant in his sideline—running surveillance cameras in stores to spy on the workers and report infractions to the owners. He also works as a bouncer in a raucous music club.

It’s there that he meets Stephanie (Marion Cotillard), saving her from a fracas and driving her home. She works with the whales at a marine park, but an accident with one of the animals leads to the amputation of her legs and the departure of her possessive boyfriend. The rugged Ali becomes his occasional replacement, nonchalantly offering to have sex with Stephanie just to test whether she still can perform in that respect. The two gradually strike up a relationship; she bonds with little Sam, and even accompanies Ali on his street-fighting excursions.

But all too predictably disaster strikes again. Stephanie’s incredible tragedy, and her struggle to come to terms with it, is followed by the collapse of Ali’s life—on a far smaller scale, perhaps, but one with severe ripple effect. His involvement in the secret-camera scheme leads to the poisoning of his relationship with his sister and his abandonment of both Sam and Stephanie. And when he tries to repair the breach with his son, the effort leads to even greater disaster. The latter reels of “Rust and Bone” represent a piling-up of bad things happening, and Audiard proves incapable of concealing the melodramatic mawkishness in what becomes a positive orgy of loss and near-despair. He’s attempting the same sort of subtle dissection of life among the marginalized that the Dardennes have so brilliantly managed, but falls into the trap of kitchen-sink soap opera more representative of the worst examples of 1950s American “socially conscious” writing.

That’s despite the fact that his cast brings real humanity to their roles despite the script’s obvious calculation. The effects work that makes Stephanie’s prosthetic legs palpably real are certainly an element of Cotillard’s performance, but she transcends that gimmicky part of the role, using her natural radiance to brighten a dowdy character that might have been simply depressing. Schoenaerts easily convinces from a purely physical perspective—the fight scenes are brutally realistic, though the focus of the director and cinematographer Stephane Fontaine on the battlers’ mid-sections comes across as unseemly. But he’s equally good at expressing Ali’s sheer animal power—the character has a lot of the outcast from “The Beauty and the Beast” in him—though the picture is as far from Cocteau as could be imagined. The supporting cast is all fine, with Verdure standing out as a tyke so true and lovable that you just know the cycle of tragedy will eventually engulf him.

In addition to the fine visual effects, the technical side of “Rust and Bone” is appropriate to the director’s neo-realist approach. But the Dardenne-inspired look of the film unfortunately conflicts with the script’s more purple plot turns. There are powerful moments here, but their impact is undermined by a lack of subtlety in the storytelling.