The girl got into the car, parked in the family garden near the coastal town of Boulogne, while each of her parents thought the other was looking after her.

According to preliminary reports, the girl became ill due to the intense heat and died after spending no more than an hour and a half in the car, which had one door open.

"It was a tragic domestic accident," a spokesman at the local public prosecutor's office said.

A police enquiry has been opened.

The girl was not the first victim of the extreme weather in France.

Brush and forest fires in the south of the country have claimed four lives; two Britons, a Pole and a French woman.

TERRA.WIRE