For centuries, the Seine was Paris's source of life and daily refreshment. Long before modern pools and tap water, Parisians washed clothes, drew drinking water, and cooled off in the river's flowing current.

In summer, families would gather at the quays, where men and boys dived from bridges straight into the open water. In 1781, the French writer Louis-Sebastien Mercier described this everyday scene in his Tableau de Paris: "One sees, in the warm season, men and boys plunging into the Seine from the bridges and quays; these baths are taken in full daylight."

As the city grew during the Industrial Revolution, Parisians turned to floating bathhouses for a more organized swim. The famous Piscine Deligny opened in 1796 on a moored wooden barge, offering changing rooms and safe river access. By the late 19th century, the Seine hosted more than 20 such facilities. In 1913, the river even staged the French Diving Championships, a fitting symbol of a city deeply connected to its river.

But by the early 20th century, Paris's industrial boom brought severe pollution. Waste poured in from riverside factories and untreated sewers, turning the once-clear Seine into an unsafe waterway. After the World War I, city officials tested the water and found contamination too risky for human contact. In 1923, Paris formally banned swimming in the Seine, a prohibition that would last a century. Over the decades, the city made repeated attempts to restore the river's health.

In 1988, then-mayor Jacques Chirac stood by the riverbank and boldly declared: "I will bathe in the Seine in front of witnesses to prove that the Seine has become a clean river." But the deadline he set, 1994, came and went without any swimmers in sight. For 30 more years, various city plans to clean the river stalled amid competing priorities and political debates.

The Seine's return as a swimming spot seemed little more than a nostalgic dream, until Paris won the right to host the 2024 Olympic Games.

The Olympic Games gave Paris a clear deadline and a powerful incentive to deliver on old promises. Starting in 2015, the city, the national government, and local authorities across the northern France region invested more than 1.4 billion euros ($1.63 billion) in an ambitious plan to clean the Seine. They upgraded wastewater treatment plants, rebuilt sections of the city's underground sewer system, and improved rain overflow controls to keep stormwater from contaminating the river. Environmental groups and skeptics questioned whether it would be enough. Media outlets ran headlines mocking the effort, warning that Paris's athletes might swim "in poop."

Still, the city pressed on. In the summer of 2024, the world watched as triathletes and marathon swimmers plunged into the newly-cleaned Seine for the Olympic and Paralympic events near the Alexandre III Bridge, without incident. For Parisians, the sight of elite athletes gliding through the water was proof that a cleaner Seine was more than just talk.

After the Games, the city announced the opening of three permanent public swimming sites: one by the Eiffel Tower, one near Notre Dame, and one in eastern Paris. In July 2025, thousands of locals and tourists lined up for a chance to jump in. Heavy rain briefly suspended swimming for a day, but people returned as soon as it reopened. Lifeguards now patrol, water quality is checked daily, and crowds float under the summer sun.

Paris's century-old ban has finally lifted, and what began as a place for washerwomen and boys leaping from bridges has become a symbol of urban renewal — and a promise kept, even if it arrived 100 years late.