“What if there were a shark in the Seine?” is, one can only assume, a question that Parisians ponder on a daily basis. It’s also brilliant in its simplicity, if not quite as appealingly silly a high-concept premise as “what if there were snakes on a plane?” and “what if the moon … fell?” Look no further than “Under Paris” for an answer to the hypothetical that surely keeps Emmanuel Macron up at night, as Netflix’s new thriller swims rather than sinks as it adds life to a genre that’s been bloodless for far too long.

Most importantly, director Xavier Gens (“Lupin”) plays it straight — there’s no winking at the crowd or so-bad-it’s-good posturing, just killer set-pieces and a firm understanding of the fact that the best creature features are those in which you see the creature as little as possible.

In much the same way that Godzilla was driven to his city-destroying ways by radiation-emitting nuclear tests, Lilith (as our apex-predator antagonist is somewhat endearingly known) seeks refuge in France’s iconic river after pollution drives her out of her saltwater home. “Under Paris” makes its environmental underpinnings clear in the opening sequence: a trip to the depressingly vast Great Pacific Garbage Patch in which researchers led by Sophia (Bérénice Bejo) swim into the wrong side of a mako feeding frenzy. That includes her husband, whose off-screen death is made explicit by a floating hand sporting a pristine wedding ring — the first of several memorable images courtesy of Gens and DP Nicolas Massart.

Others include a blood-soaked Sophia emerging from the water after her own close encounter, Lilith sending one of those activists to a watery grave and a sequence set in the Catacombs you’ll have to see to believe. Gens is a visual storyteller first and foremost, which fits the material like a wetsuit. There isn’t any dialogue as instantly quotable as “You’re gonna need a bigger boat,” but as a sensory experience, “Under Paris” is never less than seaworthy.

Three years after the tragic inciting incident, Sophia finds herself caught between the police and a youth-driven activist movement as both groups contend with the fact that, well, there’s a shark in the Seine. Lilith’s arrival is made especially urgent by an upcoming triathlon whose swimming portion is scheduled to take place in the river. In true shark-movie-mayor fashion, Paris’ top official is loath to delay the event over safety concerns, much less cancel it.

The fact that you can already tell where this is all headed might make you smarter than the fictional mayor, but it’s unlikely to hinder your enjoyment of the inevitable climax. Syfy-esque premise notwithstanding, “Under Paris” (the original title, “Sous la Seine,” is, unsurprisingly, much more pleasing to the ear) is a smart blockbuster that would have been best experienced on the big screen — especially given how anemic the summer box office has been thus far.

If you can resist the joy of Bejo repeatedly declaring “c’est pas possible” upon being confronted with yet another seeming impossibility — such as, oh, the fact that mako sharks don’t live in freshwater — then perhaps your time would be better spent rewatching her Oscar-nominated turn in “The Artist” instead. You’d be missing out, however, as “Under Paris” is so assured in its plotting that it doesn’t even qualify as a guilty pleasure — and, for the record, there is an explanation for Lilith’s unique adaptation.

Few movies deserve the “often imitated, never replicated” designation quite like “Jaws” does, as every truly great shark movie that has followed in its wake can be counted on one hand with a few missing fingers. “Under Paris” might just be the best of them, which isn’t the faint praise it might sound like.

Reviewed online, June 4, 2024. Running time: 104 MIN.

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