Pinturault's second run was timed in a sizzling 47.33 seconds and gave him a combined-run time of 1 minute, 36.55 seconds -- 0.57 seconds ahead of Felix Neureuther of Germany.
"I am pretty surprised," said Piturault, who notched his first career victory in the slalom. "When I crossed the finish line in the second run and saw my advantage I could hardly believe it."
Marcel Hirscher of Austria led after the first run and ended up in third place with a 1:37.12.
Ted Ligety was the top U.S. finisher, in 12th place, which was good enough to keep him in second place in the overall World Cup standings behind Norway's Askel Lund Svindel.
Snow conditions at Val d'Isere remained soft following a heavy snowfall earlier in the week. However, the lighting on the course was improved and helped the competitors navigate.