The contract also includes long-term service and maintenance works.
A balance of plant contract has been signed with Belgian marine engineering Deme group for the installation of the turbines.
GeoSea, member of the Deme Group, is scheduled to commence construction of project, previously known as Meg I, in 2016.
Located 45km north of Borkum in the North Sea, the wind farm will be built and operated by Merkur Offshore, a joint venture of DEME Concessions Wind and Windreich.
Alstom Renewable Power president Jérôme Pécresse said: "This is the largest offshore wind contract signed by Alstom outside France on a major and significant market, coming after the winning of the construction of the first offshore wind farm in the US.
"The Merkur Offshore contract is also the first offshore wind project led by Alstom in Germany, which is particularly important for our further business development in Germany and Northern Europe."
Alstom will manufacture the offshore wind turbines at its new facilities in Saint-Nazaire, France.
DEME Group CEO and director Alain Bernard said: "Combining favorable sea bed conditions with one of the strongest and most reliable wind resources in the world, Merkur Offshore will be one of Germany’s largest wind farms in the North Sea, contributing significantly to Germany’s energy transition plans and the European clean energy targets."
