The victory gave Djokovic back-to-back ATP Tour titles after his win over top-ranked Roger Federer in the Swiss Indoors final last Sunday.
The third-ranked Djokovic also beat World No. 2 Rafael Nadal in the semifinals in Paris and will be a strong favorite when he'll try to defend his title at the eight-man ATP World Tour Finals from Nov. 22-29 in London.
"Winning back to back titles at this level is a huge achievement for me, and adding to that, beating the World No.1 and No. 2," Djokovic said. "I really feel that I'm in great form right now."
The Serb looked set for a comfortable triumph after winning the first set in just 30 minutes, but then struggled to stay at the same level.
"It was unbelievably difficult," said Djokovic, who has won a record 76 matches on the tour this season and claimed his first Masters 1000 tournament of the year following defeats in four finals.
"Gael was very unpredictable and he was hitting the ball very good," said Djokovic, who is 4-0 against Monfils.
Djokovic will defend his title at the eight-man ATP World Tour Finals from Nov. 22-29 in London.
The former Australian Open winner fell on his knees and screamed on the center court when Monfils -- who was chasing his third career title -- double-faulted on the first match point to give Djokovic his 16th career title.
"I didn't find any solution in the beginning, I was playing too defensive", Monfils said. "But I didn't lose faith in my chances and I almost overturned the match."
Losing only three points on his serve in the first set, Djokovic pumped his fist when he took a 5-2 lead with a forehand winner down the line. He won the set in the next game when Monfils hit his first double-fault.
But Djokovic made 21 unforced errors in the second set and Monfils finally gave his supporters something to cheer by converting his first break point of the match in the fifth game after Djokovic missed an easy backhand volley.
Monfils then leveled at 3-3 and kept the pressure on Djokovic, failing to convert three other chances to break before taking the Serb's service with a return winner for a 6-5 lead.
In the final set, Djokovic broke in the fourth game with a little help from Monfils, who lost his serve with his third double-fault of the match. Djokovic also double-faulted on Monfils' break point in the seventh game and the 15th-seeded Frenchman leveled at 4-4 and eventually force a tiebreaker.
"The support of the crowd was one of the probably crucial things of today's match in his favor," Djokovic said. "So that makes my success even bigger."