The man, believed to be around 20 years old, was found in a lay-by near the village of Val-des-Près, just a few kilometres from the border, by a truck driver at around 3 am on Thursday morning.
“He had not been run over by a vehicle,” a police source said.
The driver was trying to help him when a French border police patrol came across the pair and called in an ambulance. Paramedics found the man suffering from hypothermia and cardiac arrest but were unable to help him and he was declared dead when taken to hospital in the nearby town of Briançon.
Local prosecutors said they had opened an investigation into “manslaughter and endangering the lives of others” over the death of the young man, whose identity and nationality, if known, have not been made public.
A similar investigation was opened in May last year when the body of a young black man, presumed to be a migrant, was found by walkers in the nearby Montgenèvre area.
Several charities, including Amnesty International and the local Tous Migrants group, in December warned threat they feared that migrants crossing the Alps from Italy into France could die if more was not done to help them.
Thousands of young men, many from French-speaking west Africa, have trudged across the Alps from Italy over the past three years, dreaming of jobs and a new life in France.
Many have been tricked into paying hundreds of euros to people traffickers based in northern Italy who promise them a comfortable car ride across the border but then dump them in the Alps, leaving them to fend for themselves.