Parisians and tourists are flocking to three newly opened bathing sites on the River Seine, marking the first time in more than a century that the French capital’s waterway has been legally open for swimming. The city lifted a ban dating to 1923 after completing a €1.4 billion ($1.6 billion) cleanup that brought the river into compliance with European water-quality standards. Paris Deputy Mayor Pierre Rabadan said more than 40,000 people have taken a dip since the sites opened on 5 July, despite almost two weeks of weather-related closures. The Grenelle location, which holds up to 200 swimmers at a time, averages 800–1,200 visitors a day. Swimmers must wear a yellow safety buoy, and lifeguards monitor the designated areas, which are up to five metres deep. The reopening coincides with a heatwave that has put the Paris region on “high vigilance,” according to national forecaster Meteo France, with temperatures expected to reach 38 °C (100 °F). Water temperature in the river was measured at 22 °C earlier this week. The sites are open free of charge at scheduled times until the end of August, and daily water tests determine whether conditions remain safe.