France's first offshore turbine factories will manufacture the nacelles and generators for Alstom's 6MW Haliade turbine.
Construction of the new facility began in May 2013. The factories cover 19,000 square kilometres of space.
It was officially opened by French prime minister Manuel Valls, Alstom chairman Patrick Kron and Alstom Renewable Power chairman Jerome Pecresse.
The plant has been designed to produce 100 turbines a year, when it is fully operational next year. It will manufacture 238 Haliade turbines to be used at three French offshore projects being developed by EDF.