Under Paris

Directed by Xavier Gens, Under Paris (Sous la Seine) blends modern eco-thriller urgency with creature-feature dread. The story centers on Sophia Assalas, a marine researcher traumatized after losing her husband and oceanographic research team to an aggressive mako shark in the North Pacific Garbage Patch. Three years later in Paris, Sophia is approached by Mika, an idealistic youth environmental activist tracking a bizarre anomaly: the very same shark, nicknamed "Lilith," has migrated inland and is swimming in the freshwater of the Seine River.

As Paris prepares to host the prestigious World Triathlon Championship along the Seine—an event vital for municipal prestige—Sophia and river police sergeant Adil warn authorities of the lurking danger. However, the city's image-conscious Mayor dismisses the threat and refuses to call off the high-stakes sporting competition.

Racing against the clock, Sophia and Adil's river police brigade venture into the dark underground catacombs and subterranean waterways beneath Paris. They soon discover that Lilith has undergone radical evolutionary adaptations to survive pollution and freshwater, turning the French capital into an unprecedented hunting and breeding ground.

The core thesis of the film is that humanity's relentless pollution and environmental degradation are triggering unpredictable, irreversible natural adaptations. The central creature is framed not merely as an apex predator, but as an agent of ecological retribution born from toxic oceanic waste and urban contamination. Furthermore, the film delivers a sharp satire of political complacency, corporate greenwashing, and bureaucratic vanity, illustrating how institutions prioritize public relations spectacles and economic investments over urgent environmental and public safety warnings until catastrophic collapse occurs.

The film invites multiple thematic readings:

Released in June 2024 amid international scrutiny surrounding the environmental readiness of the Seine for the 2024 Paris Olympics, the film generated widespread social media discussion and global viewership. By combining European genre filmmaking with high-budget monster spectacle, the production demonstrated that non-English eco-horror could achieve record-breaking international streaming numbers while bypassing standard Hollywood narrative formulas with an apocalyptic conclusion.

Audience and critical response highlighted several distinct elements:

• Strengths: Praise centered on the bold apocalyptic climax, high-intensity catacomb sequences, strong visual effects during dark set pieces, and Bérénice Bejo's committed performance.
• Weaknesses: Criticisms targeted pseudoscientific liberties regarding shark biology, rapid reproductive timelines, occasional melodramatic dialogue, and uneven daylight CGI.
• Verdict: Recognized as an engaging, high-concept B-movie creature feature elevated by genuine ecological dread and an uncompromising disaster ending.