Officials warned of strong currents and riptides as they issued the highest alert level along the coastline.
ADVERTISEMENTLifeguards saved 18 swimmers from treacherous conditions at France's coastal town of Biarritz during the weekend.
Disturbed beachgoers watched as rescue teams used jet skis and low-flying helicopters to pull people out of the water.
Officials warned of strong currents and riptides as they issued the highest alert level along the coastline.
Some people were dragged 800 metres from the shore at the well-known holiday destination popular with surfers.
Dramatic video footage captured the rescue operation amid large waves. The operation was deemed to have been successful, with no injuries reported to any of the swimmers.
One local surfer told BFMTV of strong currents at the beach, saying, "Even wearing flippers and knowing how to swim well, it's dangerous."
The local government for Nouvelle-Aquitaine placed its whole coastline on maximum alert on Saturday, with people urged to only swim in areas protected by lifeguards.
Since the start of the summer, five people have drowned on the region's coast.