France full back Theo Hernandez's hooked volley in the fifth minute gave the defending world champions a 1-0 lead over Morocco at halftime in their World Cup semi-final on Wednesday.
The French, attempting to become the first team to retain the title since Brazil 60 years ago, went in front when Hernandez benefited from a deflection and beat keeper Yassine Bounou with a high volley at the far post.
France's all-time top scorer Olivier Giroud went close to adding another when he thundered a shot against the post in the 17th minute.
Morocco, bidding to become the first team outside Europe and South America to reach the final, suffered two injury blows with centre back Nayef Aguerd pulling out during the warm-up and captain Romain Saiss forced off in the 21st minute.
They came close to an equaliser, however, on the stroke of halftime through Jawad El Yamiq's bicycle kick which Hugo Lloris palmed away.
The winners will play Argentina in the final on Sunday.