The contract with Royal Caribbean International calls for one ocean liner to be delivered in 2016 with an option for a second ship, Radio France Internationale reported Friday.
The contract means more than 10 million hours of work for the shipyard, the company said.
"France is showing its capacity to win the battle for the recovery of its industry and exports," said Prime Minister Jean-Marc Ayrault in a statement.
The contract is a sign of "the excellence of French know-how in naval construction," he said.
STX France Chief Executive Officer Laurent Castaing said competition for the order with an STX branch in Finland had been "fierce."
A worker at the shipyard called the contract "a nice Christmas present."
STX France, which is along the Atlantic shoreline, has a storied past. It is where the Normandie was constructed in 1935 and where the Queen Mary 2 was launched in 2002.