The fire started before dawn on Sunday, in a building housing seasonal worker. In all, three buildings were affected.

Seventy firefighters battled to bring the blaze under control. The cause has not yet been confirmed.

Footage from the scene shows fire crews using ladders to try and rescue people from inside the three-story building.

The cause of the fire was not immediately known but around 70 firemen had brought it under control by day-break.

Local media reports say the building houses about 60 resort workers, including foreigners. Three of the four seriously injured have been taken to hospital by helicopter, local officials said.

French Interior Minister Christophe Castaner praised firefighters on Twitter and said his "thoughts are with the families and loved ones of the victims of the fire that has just plunged Courchevel in mourning."

"In the case of those seriously injured, it's impossible to specify whether their injuries came from a fall. Because the fire was on the third floor, some people jumped to save their lives," he said.

"There were carbon monoxide emissions, and there were burns."

He said local prosecutors and police would launch an investigation into what started the fire.

The pre-dawn blaze forced the evacuation of some 60 resort workers, including foreigners, from a three-story accommodation building.

Firemen found the two bodies in a burnt-out area of the building.