In order to save Paris from an international bloodbath, a grieving marine researcher is forced to face her tragic past when a giant shark appears in the Seine. A film by Xavier Gens, starring Bérénice Bejo, Nassim Lyes, Léa Léviant, Sandra Parfait, Aksel Ustun, Aurélia Petit, Marvin Dubart, Daouda Keita, and Ibrahima Ba.

During the Mission Ocean Origins Project: Evolution, marine researcher Sophia Assalas (Bérénice Bejo) and her team are en route to the North Pacific Garbage Patch, following a tagged shortfin mako shark named Lilith.

The Pacific Garbage Patch, also known as the Great Pacific Garbage Patch, is a vast area in the North Pacific Ocean where marine debris, primarily plastics, has accumulated due to ocean currents. It is not a visible island of trash but rather a dispersed collection of plastic particles, often called microplastics, which are challenging to see with the naked eye. The debris in the patch ranges from microscopic particles to large materials, such as abandoned fishing nets and other discarded items. The patch is estimated to cover an area of approximately 1.6 million square kilometers, which is roughly the size of Texas or France. It is believed to contain over 1.8 trillion pieces of plastic, weighing about 80,000 metric tons.

Upon arriving at the location of Beacon 7’s signal, Jade (Anaïs Parello) alerts everyone that she has found Lilith. Sophia’s husband, Chris (Yannick Choirat), then leads a dive team consisting of Juan (Iñaki Lartigue) Sam (Victor Pontecorvo), and Tom (Thomas Espinera), to locate Lilith while Sophia and Jade monitor them from the ship’s command center.

They find the body of a baby whale caught in nets under the garbage patch. Upon closer inspection, Chris discovers the whale’s stomach filled with plastic. He also finds an unusual and unexplained large bite mark. Jade alerts Chris that Lilith is approaching. Suddenly, a shark appears out of nowhere, shocking Chris.

Chris and Sophia are confused and curious as more female mako sharks join in. There’s no record of mako sharks hunting in packs, and these sharks’ fins appear larger than those of regular mako sharks. The dive team becomes nervous, but Sophia assures them they’re at a safe distance.

Mako sharks, also known as sharp-nosed mackerel sharks and blue pointers, are a species of swift, active, and potentially dangerous sharks belonging to the mackerel shark family, Lamnidae. There are two species of mako sharks: the shortfin mako (Isurus oxyrinchus) and the longfin mako (Isurus paucus). They are found in tropical and temperate seas worldwide and are characterized by their streamlined bodies, pointed snouts, crescent-shaped tails, and long slender teeth.

A giant, 7-meter-long mako shark glides past the dive team. Jade and Chris confirm it’s Lilith by the Beacon 7 tag on her fin. Confused, Sophia can’t believe a mako shark could grow twice its size in just three months. Driven by curiosity about this potential new discovery or scientific breakthrough, Sophia insists Chris take a blood sample from Lilith, despite his concerns about its unsafe behavior due to its abnormal size.

Shortfin mako sharks typically measure around 2.5 to 3.2 m in length and weigh from 60–140 kg. The largest mako shark taken on hook-and-line was 600 kg, caught off the coast of California in June 2013, and the longest verified length was 4.45 m caught off the Mediterranean coast of France in September 1973.

Chris stabs Lilith with a shark spear to collect a blood sample, but this unexpectedly panics her, and she swims away quickly. Lilith returns and attacks the dive team, killing all members, including Chris.

This scene exemplifies scientific inaccuracy for dramatic purpose. In real life, marine researchers would collect a blood sample from a shark in the ocean by carefully catching and restraining the shark. When a shark is caught, the researchers have about 15 minutes to take measurements, collect samples like blood and skin swabs, and implant acoustic tags before releasing it. Spearing a shark as depicted in the film, to collect blood is not a recommended practice as it would risk provoking an attack and endanger the diver, and a spear puncture wouldn’t provide a clean blood sample. Blood for research needs to be drawn carefully to avoid contamination.

Sophia races out of the control center, grabs a pneumatic speargun, and jumps into the ocean, hoping to rescue her team. However, upon diving in, she finds only Chris’s hand with his wedding ring still on it, floating in the water. Sophia confronts Lilith and fires the speargun as Lilith attacks her, but the shot misses. Lilith then drags Sophia down with a net snagged on her leg as it dives deep towards the ocean floor. The rapid rise in water pressure causes Sophia’s eardrums to rupture. Miraculously, she doesn’t lose consciousness and manages to cut herself free from the net before swimming back to the surface.

A pneumatic speargun is a type of underwater hunting weapon that uses compressed air as a propellant to fire a spear. It works by compressing air in a sealed chamber, which is then released to propel the spear out of the barrel when the trigger is pulled. This mechanism provides a high level of power and accuracy, especially at short ranges.

Three years later in Paris, two teenagers find what appears to be an artillery shell in the Seine River, presumably from World War II. The Bomb Squad is dispatched to recover the shell. Adil (Nassim Lyes), a police officer with the Brigade Fluviale de Paris, reveals that they regularly find these shells in the Seine, as they’ve already recovered over 100.

Brigade Fluviale de Paris is a police unit responsible for patrolling the Seine River in Paris. This specialized police force is composed of divers, swimmers, boat handlers, and armed officers who work together to ensure the safety and security of the river and its surroundings. Their primary roles include rescuing people who fall into the water, recovering criminal evidence, and maintaining order along the riverbanks.

Sophia now works as a tour guide at an aquarium in Paris. Her interest is piqued when a young environmentalist, Mika (Léa Léviant), approaches her and mentions Beacon 7. Mika takes Sophia to the headquarters of SOS (Save Our Seas), where Ben (Nagisa Morimoto) shows Sophia the location of the Beacon 7 signal in the Seine. This suggests that Lilith is lost and trapped in Paris. However, Sophia doubts a mako shark could survive in freshwater. She believes the tracker must have come loose and drifted there, dismissing Mika’s theory. Mika, however, is determined to help Lilith find its way back to the ocean before it dies. She tells Sophia about her plan to search for Lilith tonight near the Marie Bridge, where a car recently fell into the river with the driver missing.

Upon returning to her apartment, Sophia rushes to an old trunk and fetches her Getac laptop. She checks the Beacon 7 signal and is surprised to see it still moving near Marie Bridge. Alarmed, she races there, hoping to stop Mika’s diving mission to save Lilith.

Getac is a Taiwanese multinational technology company that specializes in rugged laptops and computers designed to withstand harsh environments and challenging conditions. Used in various industries demanding reliable computing under tough circumstances, Getac laptops find application in manufacturing, public safety, field services, and beyond. With over 30 years of experience in rugged technology innovation, Getac offers laptops with varying battery capacities and lifetimes. For instance, the Getac S410 boasts a battery life exceeding 29 hours.

Directed by French filmmaker Xavier Gens, from a screenplay he co-wrote with Yannick Dahan, Maud Heywang, and Yaël Langmann, Sous la Seine starts with a compelling premise: a female mako shark may have mutated or adapted due to plastic garbage and environmental damage. This allows it to not only grow exponentially and survive in freshwater, but also reproduce without a male.

The first twenty minutes are quite engaging, arguably the best part of the film, as they pique our curiosity about how the story will unfold. However, the film then suffers from several draggy moments where little happens. It’s also filled with unrealistic decisions and dialogue. In a monster movie like this, viewers need someone to root for.

Unfortunately, SOUS LA SEINE fails to provide such a character. Every character is either silly or erratic, making us want Lilith to wipe them all out instead. And around the one-hour mark, that’s exactly what happens – a pack of sharks slaughters a group of SOS members and bystanders gathered in the catacombs under Paris.

In Mesopotamian religion, Lilith is a spirit or demon, often associated with wind and night. She is linked to female infertility and childbirth, and her name is derived from the Akkadian word “lilitu,” meaning “night demon” or “screech owl”.

SOUS LA SEINE is neither memorable nor thrilling because its unrealistic narrative, propelling towards a conclusion that requires us to suspend all disbelief, involves a pack of furious mako sharks able to destroy the city of Paris. Well, that’s not entirely true; it’s actually the result of warmonger soldiers shooting senselessly at the shark in the river, and their bullets nicking the artillery shells sunken under the Seine. This triggers a chain reaction of explosions, flooding the entire city and destroying all the bridges.

The artillery shells sunken in the Seine River are remnants from World War II. In August 2022, divers from the river brigade and the bomb disposal squad recovered 154 shells dating back to the Second World War near the quai d’Austerlitz in the 13th arrondissement of Paris. These shells were discovered due to magnet fishing enthusiasts who raised the alarm upon their find. The recovery operation was initiated to handle the potentially dangerous situation safely, and fortunately, the shells had no ignition system, averting a potential hazard.

SOUS LA SEINE (UNDER PARIS) was released on Netflix on 3 June 2024.