Nuclear power is an important pillar in electricity generation in France. However, the French nuclear power plant fleet is ageing, and the possibility of reducing the technology's share in power generation or even a complete phase-out has been increasingly discussed. This paper focuses on three inter-related questions: First, what are the costs of phasing-out nuclear power in France? Second, who has to bear these costs, i.e., how much of the costs will be passed on to the rest of the European power system? And third, what effect does the uncertainty regarding future nuclear policy in France have on system costs? Applying a stochastic optimization model for the European electricity system, the analysis showed that additional system costs in France of a nuclear phase-out amount up to 76 billion is an element of(2010). Additional costs are mostly borne by the French power system. Surprisingly, the analysis found that the costs of uncertainty are rather limited. Based on the results, it can be concluded that a commitment regarding nuclear policy reform is only mildly beneficial in terms of system cost savings. (C) 2016 Elsevier Ltd. All rights reserved.