Farmers, hunters and local officials in the southwestern town of Luz-Saint-Sauveur called for the "immediate removal" of the brown bears, which were reintroduced to the area 20 years ago after disappearing in the early 1990s.
Thierry Lassalle-Carrere told AFP he believes a bear chased his sheep over a rocky cliff at the weekend.
"There were 309 sheep on the mountain, 125 are dead. I have been dealing with bears for six or seven years," he said. "There are attacks every year but nothing like this year. It is going to take me years to recover."
The brown bear population in the mountain range is estimated at around 30.
French farmers are often at loggerheads with conservationists over the presence of wild animals that threaten their stock.
Sheep farmers have also complained about wolves decimating their animals.
In 2014 farmers brought some 300 sheep to the Eiffel Tower in Paris to demand the right to cull more wolves than is currently allowed. A separate protest in 2008, this time against a perceived lack of support from the agriculture ministry, also saw sheep flocking around the famed tourist attraction (see below).