Polisse is all about firsts. It marks the first time auteur (auteuse? No.) Maïwenn, the sometime partner of Luc Besson, has worked from a script rather than devised her films à la Mike Leigh. It’s also the first crime-type French film in about three hundred years which hasn’t starred Jean Reno. And it’s the first film that’s ever made me walk out of the cinema actively yearning for death. Not in the same way that, say, Adam Sandler films tend to leave one wanting to set Hollywood alight and then jump into the conflagration – Polisse just made me very aware, for a few hideous, beautiful, coruscating moments, that everything’s fucking awful and that’s the end of it. This is the least appropriate ‘date film’ since Requiem for a Dream.

Life in the marginalised, underfunded and generally bloody depressing Child Protection Unit of the Paris police is grim enough as it is, even without some busybody photographer following you round and immortalising every moment you stop work for a cigarette or some chips. But unluckily for the team working under harassed chief Baloo (Pierrot), a busybody photographer is exactly what they’ve got – the earnest, bespectacled Melissa (Maïwenn) has been seconded to their department by the Home Office to document the day-to-day life of the squad. She’s really not prepared for what she finds.

For Fred (Joeystarr), Iris (Foïs), Nadine (Viard) and the rest of the BPE, the near-relentless misery of their profession is completely – perhaps unnervingly – commonplace. When a quiet day at the office can involve separating a homeless woman from her starving child, interviewing a nine year old who claims her grandfather “stroked [her] kittykat” and interviewing a teenage Romanian whose uncle forces her to pickpocket, you soon learn to normalise even the grimmest cases or risk losing your mind. Fred is more of an idealist than his colleagues and is tormented by the necessarily transient nature of his work, regularly getting himself emotionally entangled in cases despite his efforts to the contrary. He’s very taken with Melissa, but will she just drift out of his life like all the kids he tries to help?

First things first; Polisse is not a documentary. That might seem like an odd thing to assert, but it’s important – Maiwenn expertly apes the muted lighting, overlong shots and unconventional framing which might otherwise mark out a film made on the hoof with no possibility of reshoots, and when combined with the exhaustive research which went into the plot it’s very easy to forget that you’re watching what is – at least nominally – a fictional film. The occasional snatches of extra-diegetic music are carefully rationed out to ramp up the emotional tension, and the lack of resolution (just like the BPE, we never find out what happens to any of the kids who pass through their care) is at odds with the dramatic format as we have learnt to understand it. From a technical standpoint Polisse is near-perfect – if anything, it dips into the cinematic ‘uncanny valley’ of being slightly too close to the bone.

The performances are, if I’m honest, less consistent. Marina Foïs is on typically sparkling form as Iris, one of several BPE members whose implacable 9-5 masks hide fraught home lives, and rapper-turned-actor Joeystarr marks his second collaboration with Maïwenn with a painfully vulnerable performance as the passionate and conflicted Fred. Maïwenn herself is adequate if uninspired as Melissa, the photographer whose family is collapsing under the pressure of the social gulf between her and her upper-class husband, and the rest of the principal cast (which is at least eight strong) flit between unmemorable to jarringly overpresent – although Polisse did have a script, the director’s well-documented fondness for free interpretation led some of the weaker performers into compensatory overacting.

If Polisse had been a documentary, the entire ‘cast’ would have ended up being fired – the slight remove into nearly-fiction gives Maïwenn the freedom to, paradoxically, make this a more honest film than it would have been had it actually been striving after literal truth. It has its stylistic ups and downs, sure, but I suspect you’ll struggle to find a more absorbing and emotionally ravaging drama this year. Watch with caution, and try to tell yourself that it’s only a film. If only that were true.