Building on the ambitious cleanup launched ahead of the 2024 Olympic Games, Paris is now extending public access to the River Seine for swimming starting July 5 — a milestone in the city’s long-term strategy for climate adaptation, public health, and urban water revitalization.
French authorities announced this week that three designated bathing zones — at Bras Marie in central Paris, Grenelle to the west, and Bercy in the east — will welcome swimmers for the first time in over a century, depending on weather conditions. “For the Games, we cleaned up three quarters of the Seine. And the water was 100 percent ready for bathing on dry days,” said Marc Guillaume, the Ile-de-France prefect, emphasizing the long-term nature of the city’s water quality efforts.
The initiative, part of the multi-billion-euro "bathing plan" leading up to the 2024 Paris Games launched in 2016, focused on updating the capital’s antiquated wastewater infrastructure. With over €1.4 billion invested since 2016 — in addition to €9 billion since the 1990s — the plan aimed to intercept stormwater overflow and separate it from the city’s sewage lines.
“Making the Seine swimmable is first and foremost a response to the objective of adapting to climate change, but also of quality of life,” Paris Mayor Anne Hidalgo said. Her symbolic plunge into the river ahead of the 2024 Olympics underscored both environmental ambition and public commitment.
Real-time monitoring will be at the heart of the system. Bathing sites will feature pollution flags, signaling water quality based on rainfall and bacterial presence. “We’re not tossing a coin, we’re relying on scientific data,” said Paris deputy mayor Pierre Rabadan. E. coli and enterococci levels will be measured daily, using both sensors and samples. However, the plan has critics.
According to France Nature Environment Ile-de-France, the monitoring regime may not go far enough. “There are many viruses which cannot be tested for,” said honorary president Michel Riottot, citing risks such as hepatitis and gastroenteritis from accidental ingestion. Chemical pollutants, too, remain largely untracked.
Still, ecological indicators point toward improvement. The number of fish species in the Seine has jumped from just four in 1970 to 36 by early 2025 — a sign of better oxygenation and cleaner water.
In a landmark move, the Seine was granted legal personhood this month, further signaling a new era in waterway stewardship.
As Rabadan concluded: “If there is occasional pollution upstream, we will be informed, so we will be able to take necessary measures.”
