Overview

• Three supervised zones—bras de Grenelle, bras Marie and Bercy—opened on July 5 for daily public bathing through August 31.
• Real-time sensors and culture tests monitor bacterial levels and river flow, with green-yellow-red flags used to close sites when water quality or weather risks rise.
• Swimmers must pass an on-site aquatic ability assessment, meet age and size criteria, wear approved swim attire and shower before entry.
• Authorities have spent over €1.4 billion since 2016 on Seine and Marne pollution control and allotted nearly €14 million for this summer’s bathing infrastructure.
• Additional free swimming areas on the Marne are already welcoming bathers and city planners are evaluating new Seine sites for a permanent 2026 program.