The Seine used to be a toxic mess. Now it’s the hottest new swim spot in Paris

If you’re visiting Paris this summer, you might want to add swimming in the Seine River to your itinerary. And you might definitely need it after the heat this city has seen over the last few weeks.

Paris experienced its hottest day in history in late June, with temperatures reaching 104 degrees Fahrenheit (40 Celsius). With the arrival of the third heatwave next week, the opening of three swimming spots along the river could not have come at a better time.

Starting Saturday, Parisians and tourists can take a refreshing dip in the River Seine for the second summer in a row. A centuries-old ban has been replaced by what is quickly becoming a new Parisian summer tradition.

Saturday’s seasonal opener was planned to commemorate the 250th anniversary of French-American friendship. For American visitors, there could be no more quintessentially Parisian way to celebrate the Fourth of July than taking a dip in the Seine River.

in water for centuries

While many consider river swimming a modern innovation, Paris has a deep and complex history with the River Seine.

It all started as an ordinary, bare practice on the sloping banks of the river in the 17th century; This habit was first banned on the grounds of foreseeable public decency in 1716. This restriction gave way in the 18th century to floating baths: canvas-covered flat-bottom boats in which bathers descended internal stairs to swim directly in the current of the river within a marked safety area.

By the 19th century, bathing had evolved from a quick way to cool down to a major social and sporting event. Wealthy establishments at banks offered restaurants, cafes, and swimming lessons. One of these, Piscine Deligny, became one of the city’s most popular venues and eventually hosted the swimming events for the 1900 Paris Olympics.

The river’s golden age began to fade in the early 20th century. A wave of drownings and river traffic accidents led the French government to ban swimming altogether in 1923.

Deligny managed to evade the ban by rebuilding itself as a floating, filtered pool separate from the river water, and continued to exist as a Parisian institution until it mysteriously sank in 1993. Elsewhere, unauthorized bathing nevertheless continued, especially in hot weather, and the long-distance swimming race, held since 1905, continued unchallenged by the authorities.

biologically dead

But the real death of Parisian swimming culture did not come from rules and regulations; This was due to pollution.

Water quality declined catastrophically throughout the mid-20th century. By the 1970s, the River Seine was essentially a flowing urban cesspool: More than half of the region’s wastewater was dumped directly into it without treatment. The loss to the ecosystem was almost fatal, and by 1970 the river was effectively biologically dead, with the fish population reduced to just three resistant species.

Serious efforts to reverse the damage began in the mid-1980s, resulting in a political promise that would haunt the French leadership for a generation. In 1988, Paris mayor Jacques Chirac, running for re-election, made a bold promise to swim the Seine River in front of witnesses within three years to prove that the river was clean. He repeated the quote on television in 1990, but it never materialized and he turned it into a joke. The Seine remained stubbornly poisonous. As recently as 2013, the Paris triathlon had to be canceled entirely because the water quality was too dangerous for athletes.

Billion euro solution

The specter of Chirac’s promise was finally revived in 2016, when mayor Anne Hidalgo revived it ahead of the city’s 2024 Olympic bid. This time, it took more than a billion euros and a monumental engineering project to overhaul the French capital’s wastewater treatment system and connect thousands of riverside homes to the sewer network for the first time.

The centerpiece of the operation is the largely underground cave basin excavated near Gare d’Austerlitz. The structure is a huge concrete cylinder, 50 meters wide and 30 meters deep, supported by pillars buried deep underground, capable of holding 50,000 cubic meters of rainwater, the volume of approximately 20 Olympic swimming pools.

Because Paris’ existing sewers, built during Haussmann’s 19th-century modernization of the city, combined rainwater and wastewater in the same pipes, heavy rain always sent the overflow directly into the river. This excess is now directed to the Austerlitz basin, kept underground until the weather improves, then slowly pumped to treatment plants outside the city. Officials say the system has reduced the number of major sewer overflows in the River Seine from 15 to about two a year.

go back to water

The operation was timed to be ready for the Olympic triathlon and marathon swimming events. Although some athletes later reported illness, no clear connection to water was confirmed, and the centuries-old psychological barrier to bathing in the Seine was finally broken. Despite the city’s trademark skepticism, nearly 100,000 people showed up for the first public season in 2025.

This summer, the city improved its layout by offering three separate, free public swimming areas.

On: Bra MarieBeneath the 19th-century Pont Louis-Philippe near Notre-Dame, bathers are treated to a truly Parisian view of the old city.

GrenelleLocated further west, it offers swimming with direct views of the Eiffel Tower while overlooking a quarter-scale replica of the Statue of Liberty.

BercyLocated in the east of Paris, it is the largest of the three and the best for anyone looking for a real workout: one of its two pools is 67 meters long, and across the water is the Bibliothèque Nationale de France.

A rite of passage

A word of warning: this is not the Côte d’Azur. The water is khaki rather than turquoise, and swimmers may encounter the odd floating debris, and the smell leaves something to be desired. But the experience makes up for it.

As with beaches, there is a system of flags to indicate whether swimming is safe: green means it is good to go, yellow means proceed with caution, often due to strong currents or storms, and red means swimming is not allowed due to poor water quality or weather conditions.

The system is not infallible. Last July, the green signal was raised on only 18 of 31 days. That’s because the city conducts daily testing for signs of sewage contamination, primarily E. coli, at multiple points along the river. If the signal is red, swimming spots are out of bounds for a day or two while the river cleans itself.

But the momentum is undeniable. Drawing on its sporting roots, the Grenelle region will host open water and high diving events for the European Swimming Championships later this month; This competition is held in Paris for the first time since 1931.

Whether the rather expensive cleaning is worth it remains a matter of debate among Parisians. But as the next heat wave arrives and the city begins to warm up again, the decision may become clearer if more people finally decide to take the plunge.

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