GDF said that its new acquisition has a "significant" pipeline of onshore wind projects under development, amounting to 200MW. West Coast will become GDF's core onshore wind development business in the UK and will continue to operate from its base in Mold, north Wales.
Since 2008, the two companies have worked together on the development of a number of projects in the UK with a total capacity of 49.6MW.
GDF said that the acquisition strengthens its "commitment to expand its wind portfolio in the UK" and confirms its strategy of "pursuing growth in renewable generation in Europe".
West Coast has been operating in the wind industry in the UK for 18 years and has been involved in the development of 9% of all onshore wind capacity in the country.
Chairman of West Coast Gerry Jewson said that the acquisition was necessary if the company was to prosper in a "changing and competitive energy policy environment".
The financial terms of the deal were not disclosed.