High-altitude lakes are vulnerable ecosystems that require protection and sustainability management, although their overall functioning is still poorly understood. In France protected area managers and scientists are cooperating to address this problem. Their results show the huge diversity of these altitude lakes and imply specificities in their functioning and in the way they respond to stressors. Multidisciplinary studies on these ecosystems, on their individual history and the stressors they face, need to be developed in a number of lakes, alongside long-term monitoring surveys. This is the objective of the Sentinel lakes network.