Citizen participation to water management is becoming more important regulatory wise and appears as a profound social aspiration. The implementation of participatory actions under Integrated Water Resource Management (IWRM) is now a part of the manager’s mission. Which would suggest a new way to manage and work. In France, the water legislations set the guidelines of the participatory approach, but implementation modalities remain vague and raise questions as to the objectives. With this ambiguity, managers have plenty of flexibility but also uncertainties on its own terms and merits. Implement water management strategies require dealing with a large range of actors and actions with various objectives and forms. In this paper, by the analysis of French watershed management implementation in the regional nature parks, we present some reasons which highlight the complexity linked with citizen participatory approach. Looking at local authorities answers related to the institutionalization of participation, allows us to identify the main challenges to improve the participatory approach of IWRM according to the feedback of the Regional Nature Parks.