In Paris, residents and tourists will be able to swim in the Seine again from 2025 for the first time in over 100 years, Mayor Anne Hidalgo announced.
She named the three sites that will be open to the public, an aquatic centre already partly in use, as well as two more central swimming spots, not far from the Eiffel Tower.
The swimming areas will be demarcated by buoys and accessible via a jetty. There will be changing rooms and showers provided, the city said.
Being able to swim in the Seine again has been a long-standing wish for Parisians.
Swimming in the city's river was officially banned in 1923 due to the poor quality of the water, but was still practised until the early 1960s.
The project has now been given a boost by the 2024 Olympic Games set to be held in Paris. Some of the swimming competitions will take place in the Seine.
Extensive efforts to improve the water quality are under way. The city says it has already invested up to 1.4 billion euros ($A2.3 billion) to make the Seine cleaner for the greater Paris area.
"This is a long-cherished dream and it is well on its way to finally becoming a reality," the city announced on Sunday.
"Safe bathing in the Seine will be possible."
