The operation is part of an ambitious investment programme on the bio-environmental transition and the fight against global warming, undertaken on several buildings of general interest on the island. These are the thermal and energy renovations of the Concordia National Gendarmerie Barracks. The project provides for 7 areas of intervention: 1: Thermal insulation from the exterior of buildings; 2: Replacement of exterior joinery (doors and windows) with generalised double glazing and acoustic doors; 3: Deployment of a rainwater recovery device of 30000 litres in order to maintain parks and gardens in particular. The drinking water in Saint Martin comes entirely from a process of desalination of seawater that generates considerable electrical consumption in a context of fully carbonated electricity production. 4-: Creation of a drinking water management system to cope with cyclonic events. Recent climate events have shown the extreme vulnerability of public services in charge of protecting civilian populations in times of crisis. In order to increase the effectiveness and efficiency of public services in charge of law enforcement and civil peace during these complex periods, the project provides for the creation of a buffer tank for access to water, including during cut-off periods 5 – It is envisaged to deploy a system