Spoiler warning: Spoilers for the complete film.
Sophia and Adil survive, Lilith survives, and Paris is flooded. Under Paris ends with the scientist and police officer temporarily above the water while the sharks occupy the city around them.
Why does the plan fail?
The attempt to destroy the nest does not kill Lilith. She reaches the triathlon, and the military response triggers old explosives in the river, setting off a wider destruction of bridges and infrastructure.
The flood turns a contained threat in the Seine into a transformed urban environment. The response meant to stop the animal has made far more territory accessible to it.
The film’s chain of events is a fictional disaster mechanism, not evidence that contemporary Paris faces this scenario. The shark’s extreme adaptations belong to that same invented premise.
Why isn’t killing one shark enough?
Lilith can reproduce without a mate, and her offspring are already reproducing. The problem is therefore a population capable of expanding, rather than a solitary predator that happens to be in the wrong river.
Sophia’s warnings concern that changing scale. The mayor’s insistence on preserving the event treats the danger as a disruption to manage publicly instead of a condition requiring cancellation and action.
By the time the city understands the stakes, the original opportunity to contain them has gone.
What do the final images confirm?
Sophia drags the weakened Adil to a metro entrance, and both remain alive. Lilith and other sharks circle nearby. Their survival is immediate and precarious, not a completed evacuation.
The end-credits map extends the spread beyond Paris to other cities. It signals the potential scale of the disaster without providing a detailed future for the two protagonists.
The ending is bleak because recognizing the threat does not reward the characters with control over it. They understand what is happening and have survived long enough to see the consequences. That knowledge leaves them on a small piece of high ground inside a city whose familiar geography no longer protects them.
Sources: official ending breakdown.