Claude Jager, born in 1940 in Elvange, Moselle, is a French mountaineer and guide. He discovered the mountains during his studies at the National Institute of Applied Sciences in Lyon, where he befriended climbers such as Marc Martinetti, Jean-Paul Paris, and Yannick Seigneur, with whom he completed his first mountaineering expeditions. An aspiring guide since 1964, he opened numerous new routes in the following years. Appointed a teacher at the Lycée du Fayet, he met Walter Cecchinel, with whom he completed a series of remarkable winter ascents.