This paper examines the role of experimentation in devising coastal adaptation policies. It is based on an in-depth study of one such experiment organized by the French Ministry for the Environment from 2012 to 2015. In the experiment studied, a small number of coastal municipalities volunteered to simulate the implementation of planned retreat to their respective areas. These exercises involved the participation of state services, local authorities, and various local stakeholders. Using insights from discursive institutionalism, we tracked developments throughout the experimentation period, highlighting the social and political dynamics attached to policy making and the legitimization of planned retreat. We first argue why it is critical to re-introduce political dimensions (polity, politics and policy) when analyzing stakes involved in such experiments, and how we did so. The French planned retreat experiment is presented both as a governance process of experimentation and an example of the French government aiming to steer current and future coastal policy "at a distance". The tensions between these two forms of governing were taken into account, producing multi-level empirical results. At subnational level, the friction between these two forms of governance is examined through a case study of the Aquitaine Region in southwest France. Three experiment sites located in this area are all managed and coordinated by a single body: the Aquitaine Coastline Public Interest Group. Its position as a key player at the intersection of different worlds and the projections applied to it are the main features that mark it out as a “boundary entrepreneur”. We show how the resources and ability of this group to carry out political boundary work were key features of the experiment from start to finish, and how the organisation developed learning processes in the regulation of local conflicts. The planned retreat experiment has opened new ‘political space’ for potential changes in the legal and financial regulations governing coastal risk management. However, as we show, the technocratic nature of existing French coastal risk management systems severely limits the chances of planned retreat policy being institutionalised in the near future.< Leer menos