People swim in the Seine river after Paris Mayor Anne Hidalgo swam in the river, Wednesday, July 17, 2024 in Paris, France. (AP Photo/Michel Euler, File)

FILE - Paris Mayor Anne Hidalgo, center, in the background, swims in the Seine river, Wednesday, July 17, 2024, in Paris, France. (AP Photo/David Goldman, File)

FILE - Paris Mayor Anne Hidalgo swims in the Seine river Wednesday, July 17, 2024 in Paris, France. (AP Photo/Michel Euler, File)

FILE - A view of the Seine river in Paris, Wednesday, April 5, 2023. (AP Photo/Christophe Ena, File)

FILE - Senior technician Omar Bach-Rais tests water samples from the Seine river for analysis as Aurelie Lemaire, a microbiology research intern looks on, in Paris, Wednesday, April 5, 2023. (AP Photo/Christophe Ena, File)

Competitors dive into the Seine river at the start of the men's 10km, marathon swimming, at the 2024 Summer Olympics, Friday, Aug. 9, 2024, in Paris, France. (AP Photo/David Goldman, Pool)

Competitors dive into the Seine river for the start of the marathon swimming men's 10km, at the 2024 Summer Olympics, Friday, Aug. 9, 2024, in Paris, France. (AP Photo/David Goldman, Pool)