The 21-year-old was on target for the seven-time champions in their 4:0 win against visiting Lorient.
Earlier in the day N'Jie had agreed a deal to remain at Lyon until 2019.
"I'm happy" - Now we have to continue working.
I want to score, to play and I hope we can qualify for Europe next season," he told Lyon's website:
"I'm proud of myself."
I want to also thank everyone who helped me get this far.
This extension shows that the team has confidence in me."
N'Jie has made a superb start to his international career with the Indomitable Lions.
He scored on his debut on 6 September in a 2:0 win away to Democratic Republic of Congo and four days later he grabbed a brace to help Cameroon beat Ivory Coast 4:1.
