Harvesting renewable marine energies (RME) will allow coastal regions to deploy a consequent contribution to the effort to reduce carbon emissions worldwide. However, as with any large-scale development in the marine environment, it comes with uncertainty about potential environmental and societal impacts, most of which have not been adequately evaluated yet. Across Europe, offshore wind farms have a total capacity of almost 3 gigawatts (GW), according to the European Wind Energy Association. By 2020, France plans to add up to 6 GW and on July 11th 2011, the French government opened a call for project proposals for 5 zones off the northern and western coasts. The development of less mature technologies (such as tidal turbines or wave energy converters) is also supported through demonstration projects. Concerns regarding the potential environmental and societal impacts which may be caused by the installation of such devices and their associated infrastructure (including substations and subsea cables) have to be carefully investigated. These include the potential impacts on the biological, physical and human environments. The novelty of EMR technologies and the related new usage of the coastal zone imply that there are few hindsight and important gaps of knowledge. The “France Energies Marine” (FEM) project, supported by a large public-private partnership, aims to speed up the development of renewable marine energies in France by 1) consolidating scientific expertise, 2) testing and validating the technologies and 3) preparing future jobs through appropriate training. It recently answered to a national call for tenders for “Institutes in decarbonated energies” and is still currently under examination. This 10-year project would be based in Brest (West Brittany) and will include various institutions such as public scientific institutes and private industrial companies. The scientific objectives of the FEM project are to tackle technologic gaps and to solve non-technologic (especially environmental and societal) questions. The non technologic research field aims to better assess the potential impacts cutting across all RME technology types (i.e. offshore wind, tidal current, wave and thermal gradient) through the construction, operation, and decommissioning stages as well as across spatial and temporal scales. To date, the main concerns over the potential negative impacts of MRE installations on biodiversity are habitat loss and disturbance caused by noise (during the construction phase) and electromagnetic fields produced by the power cables. Potentially positive impacts (e.g. reef effect of artificial structures) are to be considered as well. There is an urgent call for research on these issues, and related scientific research is just beginning through collaborative national and international works.