The avalanche occurred at the ski resort of Entraunes, on the edge of the Mercantour National Park in the Alpes-Maritimes department.
The local gendarmes said that as well as the four fatalities there was also another person missing and one person injured.
❗️ #FlashInfo Avalanche dans le secteur d'#Entraunes (06), hors du domaine skiable. Circonstances inconnues pour l'heure.
Bilan provisoire : 4 personnes décédées, 1 blessé et 1 personne disparue.
PGHM Saint-Sauveur-sur-Tinée engagé.
— GendarmerieNationale (@Gendarmerie) March 2, 2018
According to reports the avalanche was triggered just before 1pm.
Georges-Francois Leclerc, chief of the Alpes-Maritimes region, said the avalanche had struck people who were ski touring with their guide in an off-piste area near the Mercantour national park.
A rescue operation was under way. The warning level for the risk of avalanches in the area was at level 4 out of 5 on Friday, meaning snowslides were highly likely.
The south east of France has been hit by heavy snow in recent days that even saw the resort of Nice covered in a white blanket.
However temperatures have warned up in the last 24 hours which can increase the risk of avalanches in the mountains.
There have been several deadly avalanches in France this winter. Only last week a father and daughter were swept to the deaths whilst skiing on a closed piste near Val d'Isere.
A total of 16 people have died since France's ski season began in November, and 11 others have been injured.