The 50-year-old guide's body was found on Thursday morning, following the discovery of those of his clients, who were 33 and 32-years-old, on Wednesday evening.
They had been swept away by an avalanche of ice on the 4,465-metre Mont Maudit, part of the Mont Blanc massif shortly before 5.00am on Wednesday.
Rescue services were aware of the avalanche but for believed that there had been no victims until one of the guide's friends, worried that he had not returned, convinced them to take more thorough soundings of the site.
Interior Minister Bernard Cazeneuve called on mountain climbers and holiday makers to exercise "the greatest caution" in the light of 12 deaths linked to mountaineering and extreme sports that have been reported in the last seven days.
As well as Wednesday's victims:
An American plunged to his death while base-jumping in the Savoie region around Mont Blanc last Thursday;
A 67-year-old guide died in the Mont Blanc massif on Friday:
A 49-year-old monitor suffered a fatal fall from a hang-glider and a 32-year-old man using a wingsuit died in Savoie on Saturday;
A paraglider was found dead and two mountain-climbers, aged 34 and 37, died in a fall in the Alps on Sunday;
A 39-year-old woman who had been trail-running was found dead on Tuesday;
A man in his 60s died in an ultralight aviation accident on Wednesday.
A 38-year-old French base-jumper died in an accident in Norway last Thursday.