Paris reopened the River Seine to public swimming on 5 July, ending a ban that had been in place since 1923 because of chronic pollution. The city’s first bathers entered the water shortly after 8 a.m., marking the return of an activity once synonymous with the French capital’s summer life. The move crowns a €1.4 billion clean-up programme launched ahead of the 2024 Paris Olympics to make the river safe for sporting events and residents alike. Works included connecting tens of thousands of homes to the sewer network, upgrading treatment plants and building large reservoirs to prevent waste-water overflows during storms. Three lifeguarded zones—Bras-Marie near Île Saint-Louis, Grenelle opposite the Eiffel Tower and Bercy in eastern Paris—can together host more than 1,000 swimmers a day. Entry is free through 31 August, with daily bacteriological testing and a red-and-green flag system determining whether the sites open. Roughly 2,300 people took the plunge on opening day and city officials say the tally reached almost 20,000 by mid-July. Heavy rain forced the first precautionary closure on 6 July and similar weather has triggered additional short-term bans, underscoring the project’s reliance on ongoing water-quality monitoring. Paris plans to extend river swimming: fourteen additional sites are being developed on the Seine and the Marne outside the city, positioning the initiative as both a climate-adaptation measure and a lasting legacy of the Games.