One important trend in environmental policies, and especially water sector, is an increasing attention to local conditions and negotiation procedure between the different actors concerned by natural resources. Many reasons led to this evolution: the difficulty to define management rules at a central level for a resource impacted by local specifics; the necessity to involve local actors to get their agreement to apply the rules. Reunion island has experimented a new tool for planning and management of water resource -the Schéma d'aménagement et de gestion de l'eau (SAGE) on the main conflictual basin on the southern coast. This paper will related some findings of this experience. Four points will be developed: - a presentation of the water policy in Reunion island and the SAGE tool in his official form; - the situation of the southern basin, the conflict on water sharing and the actors strategies; - the process and the result of the SAGE negotiation; - the learnings on conditions of implementation, limits and interest of the SAGE procedure in Reunion context. The conclusion point out the interest of this procedure as collective learnings to overcome conflictual positions.