Police said the man had thrown himself off the 2,600-metre (8,500-feet) peak of Brevent in the French Alps at around 9:00 am (0700 GMT).
Rescue workers said he likely died on impact. He was found "several hundred metres lower in a wooded area below the site," they said.
An investigation has been launched to determine the exact cause of the accident.
On August 6, two base-jumpers, one from Switzerland, the other from France, died in similar accidents in the Alps.
A base-jump is defined as a leap off a fixed high point -- the name being an acronym for Building, Antenna, Span (such as bridges) and Earth (natural settings).
Unlike skydiving which involves leaping from an aircraft, base jumpers take off with a parachute from a fixed point, usually a cliff or a bridge.
The sport carries high risks. A Norwegian study published in 2007 concluded that base-jumping is five to eight times more likely than skydiving to result in injury or death.