After 100 Years, You Can Swim in Paris’ River Seine Again

After 100 years, Parisians and visitors are allowed to swim in the Seine again. The river, long known for pollution, is now clean enough for public swimming. What began as a Paris 2024 Olympic goal became a wider environmental shift.

The return of a swimming culture

Swimming in the Seine was common until 1923, when it was banned due to pollution.

For decades, industrial waste, untreated sewage and urban runoff made the river unsafe (paris.fr).

Massive investment in clean water

Paris invested 1.4 billion euros in water treatment plants, upgraded sewer systems and large rainwater basins.

These upgrades prevent polluted water from entering the river after storms. Today, the water is tested daily and only opened to swimmers when it meets safety standards (AP News).

Cooling the city, naturally

As summers get hotter, the Seine offers people a natural way to cool down. The river project ties into Paris’s broader strategy: fewer cars, more bikes, more green and more public space (C40 Knowledge Hub).

Wildlife is making a comeback

Researchers found DNA from 23 mussel species in the Seine—among them three nearly extinct types—showing the water is clean enough for sensitive species (The Guardian). Seals have been spotted near the river’s mouth, and fish numbers have rebounded since the 1970s.

How is water quality monitored?

The City of Paris runs daily water quality tests at all three supervised sites—Bercy, Bras de Grenelle and Bras Marie—from July 5 to August 31. Authorities check for bacteria levels, current strength, and weather conditions before allowing swimming each morning . Sites are marked with flags: green means safe for swimming, yellow indicates caution, and red means swimming is prohibited due to risks like storms or strong currents. Check out the city’s website for topical information.

Inspiration for other cities

The Seine runs 777 kilometres through France. Its revival in Paris demonstrates what long-term funding and vision can achieve—and it could inspire similar efforts worldwide.

IMPACT: What you can do next

Support local river restoration projects
Join global efforts and learn how to help protect rivers in your community. Organizations like WWF offer comprehensive guides and volunteer opportunities: WWF Freshwater Initiative.