Human remains, ski equipment and glasses had been found in 2005, high in a valley in Italy’s Aosta region.
But investigators were unable to identify the victim, and, last month, shared their findings on Facebook.
A French family then matched the glasses to a relative, Henri Le Masne, which sparked a forensic investigation.
The belongings were discovered 3,000 metres (10,000 ft) high in the Alps, near the Swiss border.
There were some clues about the man’s identity – such as clothing embroidered with initials and wooden skis, which at the time of use would have been expensive – but the investigators remained puzzled.
They established that the remains belonged to a man who would have been about 1.75 metres tall and aged about 30, with his death likely to have occurred in the spring, said Marinella Laporta, an investigator with the forensic police unit in Turin.
In June, the Aosta valley prosecutor’s findings were shared on social media with an appeal for readers to spread the information, especially in France and Switzerland.
Tutto era iniziato nel 2005, con il ritrovamento dei resti di uno sciatore sul Cervino.
Pochi oggetti intorno al corpo facevano supporre che la persona, un uomo, avesse perso la vita durante una discesa con gli sci https://t.co/adehCmuSre
— Polizia di Stato (@poliziadistato) July 29, 2018
The story was then picked up by French media.
Emma Nassem heard the report broadcast on her local radio station and questioned whether the missing man could be her uncle, Mr Le Masne, who went missing after skiing in a storm near the Matterhorn by the Swiss border in 1954.
Mr Le Masne’s younger brother, Roger, now 94, also came forward with an email describing his sibling.
“I am the brother of Henri Le Masne … who is likely the skier who disappeared 64 years ago. He was a bachelor and quite independent. He worked in the finance ministry in Paris,” he wrote in an email, which was shared with the police.
The police said a photograph provided by the family showed glasses matching those found by the investigators.
A subsequent DNA test confirmed the identification, they said.