World giant slalom champion Fenninger finished 22 points ahead of Olympic champion Maze of Slovenia in the overall standings and sealed the trophy in style with a commanding performance on the Roc de Fer course.
"It was a good season and in the end it was so tight," the 25-year-old Fenninger said. "I think we're both winners."
Fenninger finished .38 seconds ahead of countrywoman Eva-Maria Brem — her only rival for the GS title — and .46 clear of Maze, the World Cup champion two seasons ago.
Marie-Pier Prefontaine of St-Sauveur, Que., was 13th.
"Tina was so strong and I was really nervous for the second run. That's not a good thing when you feel that you're nervous," said Fenninger, who led from Maze and Brem after the first run. "I'm happy that it's the end now and I can have a rest. I'm happy to stand here with the globe."
Fenninger dropped to the floor and sobbed after seeing her winning time, while the 31-year-old Maze looked pensive as she hunched over her ski poles.
"Tina is very strong and she always comes back when it's a tough race. Today she was so strong. That's the reason why I was nervous," Fenninger said. "Tina is an unbelievable person because she's so strong and in the end she was so nice to me, because she gave me a present (a necklace) afterwards. It's always a big fight between us because at the world champs we had tight races."
Maze, who competes in all five disciplines, entered Sunday's race in a strong position after placing fourth in Saturday's slalom to open up an 18-point lead over Fenninger.
"It was for sure the hardest fight I ever had," Fenninger said. "I just tried to think about skiing and not look around at what's happening. I just wanted to think about skiing but it was hard."
Fenninger finished 106 points ahead of Brem in the GS standings. Maze was fifth in GS and third in the slalom standings.
American Lindsey Vonn, the downhill and super-G champion, finished third in the overall World Cup standings — but was 466 points behind Fenninger.
"My goal today wasn't really about the overall, just to get some points so for next year I have a good starting number so I can compete with the other girls for the title," said Vonn, who fought back this season after two career-threatening knee injuries. "It was a good day and a good way to end the season."
American Mikaela Shiffrin, who sealed the slalom title on Saturday for the third straight season, finished third in the GS standings.
Vonn finished fifth in Sunday's race and Shiffrin placed seventh.
"My goal is to be top five (in GS next season), win as many races as I can in GS and be more consistent in super-G and downhill. I won a few races but I was also 10th and seventh," Vonn said. "I'm so glad to be healthy, risk everything in every race I enter. I feel good, I'm confident and it's just so nice to be back in the World Cup. I love it."
Vonn, now fully fit and no longer troubled by her right knee, expects to mount a strong challenge for a fifth overall title next season.