The Return of Summer in Paris: Swimming in the Seine River Revived After 100 Years!

"Seine Opening" in Paris Summer—The Joy and Anxiety of a Century-Long Reopening

"The day when the river becomes the city's living room has finally arrived!"
On July 5, 2025, three authorized swimming areas in the Seine River, which flows through the center of Paris, were opened to the public. It has been 102 years since swimming was banned. The purification project, which cost approximately 1.4 billion euros (about 230 billion yen), passed the legacy to the citizens after the open water competitions at the 2024 Paris Olympicsmymotherlode.comapnews.com.

1. Open Areas and Usage Rules

• Near Notre-Dame Cathedral (4th arrondissement)

• Opposite the Eiffel Tower, Grenelle Port (7th arrondissement)

• Bercy to Villette area (12th and 19th arrondissements)

All areas are open for free from 10 AM to 7 PM, with age restrictions (10/14 years old) and lifeguards on duty as conditions. Like French beaches, a flag system of green flag = swimming allowed / red flag = not allowed is introduced, operated based on daily published bacterial test resultsmymotherlode.comeuronews.com.

2. Behind the Scenes of the Massive Cleanup

• Separation of Rainwater and Sewage: A massive 50,000 m³ adjustment pool was newly established underground at Austerlitz Station. A system was constructed to prevent sewage from flowing directly into the river during heavy rains.

• UV Sterilization Facility: Ultraviolet rays are irradiated on the final discharge to inactivate over 99% of E. coli and other bacteria.

• Mandatory Sewage Connection for Ships and Houseboats: About 150 ships moored in the Seine are connected to the city's sewage pipes.

Paris Deputy Mayor Pierre Rabadan proudly states, "The water quality is more stable than last year. While weather risks remain due to the natural environment, European standards are generally met."mymotherlode.com.

3. Four Hashtags that Exploded on Social Media

4. Is "Swimmable Rivers" a Global Trend?

The movement to open rivers in the context of urban regeneration is

• Zurich's Limmat River (since the 1980s)

• Copenhagen's Harbor Bath (since 2002)

• New York's +POOL Project (ongoing)
  and is accelerating globally. On Reddit's urban planning board, a highly rated thread is growing, stating, "Paris's case is proof that it is possible even in large cities."reddit.com.

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5. Mixed Local Opinions

6. Timeline of the Seine's Restoration (Excerpt)

• 1923: Complete Swimming Ban

• 1990s: Mayor Chirac's Declaration "Swimmable Seine in 20 Years" (Unachieved)

• 2017: Purification Project Intensified After Olympic Bid Decision

• August 2024: Olympic Triathlon and Marathon Swim Held

• July 2025: General Swimming Reopened ← Now!
  
  

7. Future Challenges and Prospects

1. Intense Rainfall Due to Climate Change: E. coli levels tend to spike 48 hours after heavy rain.

2. Ecosystem Monitoring: While 35 species of fish have recovered, invasive species are also increasing.

3. Collaboration with Local Areas: Sewage treatment conditions in upstream communes affect overall water quality.

4. Tourism Management: Noise and waste management due to overcrowding by the waterside.

"The project for Paris to reclaim the river is not ending here. The next goal is a 'drinkable Seine,'" says city project manager Claire Montanarimymotherlode.com.