Dheepan is terrific right up until a point near the end where it becomes kind of actively terrible in a really bold, gaudy way; not the first time this sort of thing has cropped up, and not likely to be the last. At least Jacques Audiard, the director and one-third of the writing team (with Thomas Bidegain & Noé Debré), has the unstinting courage of his convictions: the film's last act might be a trite failure, but it bears the mark of careful deliberation over every last detail, just like the rest of the film. And this should not be any real surprise: a decade after his international breakthrough, The Beat That My Heart Skipped, Audiard has comfortably ensconced himself as one of the leading lights of French cinema. If he wants to spend his clout on brave madness that doesn't play, then God bless 'im, he should.

Before moving on, let me nod towards the elephant in the room: yes, this won the 2015 Palme d'Or at Cannes, and no, it shouldn't have. Not in the particularly strong competition year that witnessed The Assassin, Carol, and The Lobster, just for starters. At its absolute best, Dheepan does nothing stylistically that's new for Audiard or French cinema generally, and there's something weirdly safe about the carefully-appointed message of immigrant life in contemporary France, the kind of evergreen topic that's always good for some instant credentials as Serious Art. But let's not dwell on all of that: it's a solid damn movie, no masterpiece, but a welcome addition to Audiard's career and the corpus of French message films about urban minorities both.

The film has an unbeatable hook: in the wake of his side's failure in the 26-year Sri Lankan civil war, a former Tamil Tiger named Sivadhasan (Antonyhasan Jesuthasan, a Tamil-langage political novelist acting for only the second time) decides that it would be judicious to get the hell out of Sri Lanka. In order to leave the country, he teams up with a pair of strangers posing as his family: fake wife Yalini (Kalieaswari Srinivasan) and 9-year-old fake daughter Illayaal (Claudine Vinasithamby), and the trio, under protection of passports that obliged Sivadhasan to rechristen himself "Dheepan", relocates to Paris. Here, Sivadhasan/Dheepan finds that in its own horrible little way, the life of a brown-skinned immigrant in France is just as beset by violence as the life of a refugee on the losing side of a civil war, and is thereby thwarted in his efforts to carve out a new life; Yalini and Illayaal similarly stumble through as best they can, but it's clear before very long that the best case scenario is still pretty bad, as long as they all live in France.

The rules of ethical film reviewing forbid me from saying where all this goes in more than the most general possible terms, but I think that will be enough to get it across. Since the movie's premiere Audiard has been open about the fact that he and his co-writers wanted to make a variant on Straw Dogs, and decided to set it among the Tamil population of France, rather than the other way around, which is not on its face unreasonable. "Crime thriller set among the dispossessed" is the same screenwriting Mad Libs that got us to Audiard's A Prophet, and I'll not hear a single word said against that picture. That being said, A Prophet has a beauty of a script that weaves everything that will happen through everything that has happened, and Dheepan is real solid script that has a violent finale happen at it. The film replicates Straw Dogs's basic structure of having violence only explode near the end, as a sort of "enough of this damn bullshit" gesture, but it lacks Straw Dogs's feeling of clouds gathering over the course of a feature. Even so, I think I could probably find a way to like this passage if it wasn't for what followed: a shockingly trite and completely unearned overblown happy ending that's the worst of its kind since Minority Report.

Regardless of all of that, the bulk of Dheepan is quite a lovely thing: watching the three refugees play-act at being a contented family while trapped under the pressure of being Tamil in France is so finely-tuned that it becomes almost a joy to watch, leaving no trace of the fact that we're basically watching a message picture about immigration until you stop and think about it. Audiard's shooting style, which is basically the same as in his earlier films, goes in heavily for the handheld cameras and cluttered mise en scène that have mostly characterised "realistic" European cinema in the 21st Century, but he doesn't completely give up on style: Dheepan is unusually reliant on close-ups, much to its benefit, and those close-ups tend to place us in the confidence of the characters more than would be strictly necessary if this was just another "look at these people in society" film. The three leads are distinct, interesting, complex figures, especially Sivadhasan, owing in no small part to those close-ups on Jesuthasan's spectacularly good face. By virtue of focusing so tightly on the characters, all of the more generic, prestigey elements of the film tend to fall away, and it becomes an enthralling act of watching sharply-etched people dealing with problems, in a mostly plotless way.

That makes it all the more annoying when the plot suddenly swoops in with its violent operatic vengeance, with the style changing to capture the whole of that sequence with a kind of foggy nightmare atmosphere. Which is striking as all hell, and I don't want to pretend that Dheepan becomes in some way less interesting or watchable; it just becomes much less "good", and what is satisfying about the first 90 minutes is not really anywhere to be found in the remainder of the film. It's not a movie to dismiss or ignore: even setting aside, as a general principle, that it's probably better to watch Palme d'Or winners than not, Dheepan mixes a social message impulse in with a desire to use rich characters to entertain us that serves it well and sets it much apart from the ordinary sort of gravely serious movie about the Problems Of Today. It's a worthy movie, just not an especially capital-G Great one, and that will have to be enough.