Admission is $3 for the adult swim, which runs from 11 a.m. to noon and $7 for swimming open to everyone from noon to 5 p.m. Pool parties are from 5 to 8 p.m. Cost is $100 per hour or $275 for ...

I took a breath and dived under. It was warm. Swimming had been banned in the Seine for a century, but swimmers were eager to try the clean water on Saturday.