The missed penalty proved to be a regretful moment for Gambia, as France equalized four minutes later through a strike from Wilson Odobert.
However, in the 65th minute when Mamin Sanyang, in a superb display of skill, maneuvered past the French defense before unleashing a powerful shot that beat Linard.
Making their return to the U20 World Cup for the first time since 2007, Gambia has announced its resurgence with two wins in two matches.
They previously defeated Honduras by the same scoreline.
The Gambian will face South Korea in the round of 16.
However, French goalkeeper denied Gambias captain Alagie Saine the chance to extend their lead, redeeming himself on this occasion.