The Olympique Lyon playmaker created the opener for Karim Benzema midway through the first half and netted the second 15 minutes from time as Les Bleus strengthened their lead at the top of Group D.
France, who are now on a three-game winning streak following victories in Bosnia and against Romania, have nine points from four games.
Laurent Blanc's side, however, failed to impress throughout although Gourcuff showed he has what it takes to become France's influential playmaker.
"We turned a very bad situation around. After the first match (1-0 home defeat by Belarus), we were pessimistic, but now we are top of the group," Blanc told a news conference.
"But some things did not go according to plan. Our full-backs played too high, thus forcing the midfielders to play too low and we had to correct that at half-time."
NOT ENOUGH
In a packed St Symphorien stadium in Metz, the hosts were quickly on the attack and took the lead in the 22nd minute when Benzema picked up the ball in the box from a Gourcuff corner and volleyed home to the far post.
Gourcuff, who provided the France forwards with countless chances, had an injury scare in the 54th minute when he was tackled from behind by Luxembourg captain Rene Peters, sent off for what was his second yellow card.
Hugo Lloris blocked a Guy Blaise bicycle kick on an otherwise uneventful evening for the Olympique Lyon keeper.
Gourcuff, who also scored in a 2-0 win against Romania last Saturday at the Stade de France, put the result beyond doubt when he fired past Jonathan Joubert with a powerful shot from 25 metres.
It was not enough for Blanc, who believes France should have been more dangerous.
"We did not dribble our opponents enough tonight," he said.
"We were also too slow in our passing game."
Former France sweeper Blanc, a 1998 world champion and Euro 2000 winner, was satisfied that his side had kept a clean sheet for the third successive match as he has been fielding the same centre-backs with Adil Rami pairing up with Philippe Mexes.
"Our defence is a satisfaction," he said.
"We are trying to field the same players for every game so they get along well."
Next for France is a friendly game against England at Wembley Stadium on November 17.
