Set back lines are essentially thought to protect human activities from extreme and chronic physical processes and climate change, as well as to preserve the ecosystems functions and the landscape along the coast. Setback lines are therefore established to physically separate the human activities from physical and ecological processes when it is considered necessary for the preservation of the overall quality of the system. Setback lines must be therefore thought as a tool to avoid new developments in the coastline, preserving the human cultural heritage and valuable human landscapes. It is therefore necessary to identify setback lines with a strong technical approach on one hand, which can give a clear vision of the physical and ecological dimensions of the processes and with a systematic participatory approach on the other hand, which can give a clear vision of the socio-economic implications at the local level.