The tragedy occurred near Chamonix at the Col des Montets, a mountain pass in the French Alps in France's Haute-Savoie department.
The incident took place early in the afternoon on Sunday while the man was out hiking with his wife.
The man died instantly, with his wife immediately alerting mountain rescue, according to a report in France 3 Auvergne-Rhône-Alpes.
There has been a high number of rockfalls and other landslides this summer at Mont Blanc possibly as a result of the heat wave, according to reports.
As a result of the accident, the municipality of Chamonix has prohibited access to the area.
Several climbers have also died on Europe's highest mountain this year, with three people from the same group killed in early August just days after four climbers — including an Italian man and two French women — died in the French Alps on Sunday in three separate accidents.