A section of cliff collapsed in the French beach resort of Biarritz on Wednesday, killing one woman and leaving a diver missing, local authorities said.

The collapse came at around 8:20 pm (1820 GMT) near the Miramar beach, which was packed with swimmers seeking respite from a punishing heatwave.

"According to initial information, three divers from the region were in an area at the foot of the cliff at the time of the landslide," local authorities said in a statement.

A woman's body was recovered shortly before 11:00 pm, while another person remained missing. Search efforts were called off before midnight and will resume in the morning.

The third diver, physically unhurt but in shock, was taken care of by emergency services.