This poster deals with the doctoral research of Roxanne Cesarini (PhD student, Aix Marseille Univ, CNRS, LA3M, Aix-en-Provence, France). This research is about the occupation of mountains and more precisely on settlements, mobility and economic activities in the French Southern Alps. Its aim is to shed light on the socio-economic mechanims of medieval populations in mountains and to offer a synthesis on the evolution of the medieval landscape based mainly on the archaeological and historical data which are collected.