A search helicopter was able to locate them after it picked up the signal of a special homing device the climbers were wearing, Lavergne said.
Because the area is prone to avalanches, rescuers will not attempt to recover the bodies, which are expected to resurface in "a few weeks or several years" due to the movement or melting of the glaciers, he said at a news conference.
The avalanche began at early Sunday after a block of ice as wide as two football fields cracked off a side of the Mont Blanc du Tacul, one of the peaks in the Mont Blanc range, at an altitude of 11,800 feet.
Rescuers had initially said the missing climbers were Swiss and Austrian nationals, but officials later said they included four Germans, who had been climbing together with an Austrian guide. The names of the victims had not been made public.
Seven people hospitalized following the avalanche were discharged Monday, officials said.
Avalanches intermittently hit the celebrated Mont Blanc range, where dozens of climbers die every year, from causes ranging from accidents to heart problems.
Two French climbers in a Swiss sports club died in an avalanche on Mont Blanc in August 2006. In July 2005, a British soldier was killed in another avalanche while taking part in an altitude training course on Mont Blanc du Tacul.
In Pakistan earlier this month, 11 people were killed along K2 - the world's second-highest peak - when an avalanche swept climbers away just below the 28,250-foot summit.