In a historic moment for Paris, Mayor Anne Hidalgo fulfilled her long-standing promise by swimming in the Seine, marking the river’s remarkable transformation. The clean-up operation, aimed at making the water quality safe for the upcoming Olympic events, culminated in a celebratory swim involving Hidalgo and a group of about 100 officials, athletes, and local residents.
A Century-Long Dream Realized

For the past 100 years, swimming in the Seine was considered unsafe due to severe pollution. However, on Wednesday, Anne Hidalgo, alongside other participants, took a 100-meter swim in the river, celebrating the successful clean-up efforts. The water, measured at 20°C (68°F), passed numerous tests to ensure it was safe for swimming.
“It’s a dream day … and the sun is out,” Hidalgo remarked after her swim. She reminisced about the initial discussions in 2015 when the idea of holding a triathlon in the Seine was proposed. “Today we can say they can,” she affirmed, highlighting the achievement.
Olympic Preparations and Safety Measures

Tony Estanguet, president of the Paris 2024 organizing committee, praised the collaborative efforts of city hall and French authorities in making the Seine swimmable. “Today we have confirmation that the Seine is swimmable and that the triathlon and marathon swimming competitions can take place in it,” he stated.
The successful clean-up operation included the construction of a €1.4 billion (£1.2 billion) holding and treatment tank designed to manage bacteria-laden stormwater during heavy rains. This, along with improvements to the city’s wastewater network, played a crucial role in reducing pollution levels.
In the event of heavy rain, which could cause a spike in water pollution, contingency plans have been established to postpone races by a few days to ensure athlete safety.
Historical Context and Challenges
Swimming in the Seine was banned in 1923 due to health risks. In 1990, then-Mayor Jacques Chirac promised to clean the river, but the initiative did not succeed. Hidalgo’s swim, postponed twice due to fluctuating pollution levels, finally took place just 10 days before the Olympics opening on July 26. This comes after significant efforts, including the recent operation of the stormwater treatment tank, which helped mitigate bacteria levels.
Upcoming Olympics Events

Triathlon events are scheduled for July 30, 31, and August 5, with the swimming marathon set for August 8 and 9. The paratriathlon will occur on September 1 and 2. Competitors will start their races at Pont Alexandre III, offering a picturesque backdrop of the Eiffel Tower and Champs-Élysées.
Authorities will conduct regular water quality tests at multiple points before each event to ensure safety, targeting a 75% reduction in identified bacterial pollution.
Environmental Impact and Future Prospects
The clean-up of the Seine is not only a milestone for the Olympics but also a significant step towards addressing broader environmental challenges. French experts have reported a resurgence of aquatic life in the river, with more than 30 species of fish identified, compared to just three in 1970.
Mayor Hidalgo emphasized that making the Seine swimmable contributes to the city’s efforts to adapt to the climate crisis and reduce ocean pollution. The successful clean-up operation underscores the potential for urban waterways to be rehabilitated, providing both ecological benefits and enhanced quality of life for residents and visitors alike.