In an all-Swiss big final in France, Meillard saw off compatriot Thomas Tumler after shooting out the starting blocks, before finishing in time of 20.32 seconds, with Tumler 0.25s behind him.
The result in France was something of a redemption for the 23-year-old, who was disappointed with a second-placed finish in the giant alalom last weekend in Garmisch-Partenkirchen.
After finishing ninth in the only other parallel giant slalom event of the season in Italy in December, Meillard's victory took him to 129 points in the discipline, to finish 26 points ahead of Norwegian Rasmus Windingstad, who could only manage a 28th-placed finish this time out.
Alexander Schmid rounded off the podium in third after seeing off American Tommy Ford in the small final, the German crossed the line in a time of 20.55 seconds in the bronze-medal shootout, beating Ford to the line by 0.28 seconds.
Victory in France sees Meillard rise up the overall alpine skiing World Cup standings, to ninth with 15 events still left in the season.
Norwegian Henrik Kristoffersen leads the way in the overall standings and secured his place at the summit with a solid tenth-placed finish in Chamonix, after losing out to Zan Kranjec in the quarter-finals.
Kristoffersen currently sits on 903 points after 29 World Cup events, with compatriot Aleksander Aamodt Kilde his closest competitor 47 points behind.