Joubert, who was first after the short program, landed a quadruple toe loop at the start of his routine to strengthen his lead and finished with 232.70 points for a 15-point margin over Johnny Weir of the United States. Michal Brezina of the Czech Republic was third with 217.48 points.
Japan's Miki Ando won the women's event, overtaking American Ashley Wagner in the free skate to win her second Grand Prix of the season.
Joubert tripled a planned quad salchow for his second element and did a triple toe loop instead of a quad later in his routine.
"I want to show that I am not just a jumper but a figure skater," Joubert said. "My goal was to do three quads, but I also wanted to show good choreography and good steps."
Joubert, the 2007 world champion, finished fourth at the Trophee Bompard in Paris, but improved his chances of qualifying for the Dec. 3-6 Grand Prix final.
American Jeremy Abbott, second after the short program, had a disastrous free skate and finished in fifth place with 208.45 points.
Weir started off strong with a triple flip and a triple axel, triple toe loop combination but lost stamina as the program went on.
He doubled a planned triple toe loop and failed to do the double toe loop on the next two combination jumps.
"In the Olympic season, I wanted to show a program that is pure and from the heart," Weir said. "I was happy that I was able to do that today."
Brezina was the world junior silver medalist last season and made the podium in his senior Grand Prix debut.
"I wanted to skate a clean program as I am a new face in the senior GP series," Brezina said. "I was happy to do that today and finish on the podium."
Japan's Daisuke Takahashi, who is making a comeback after knee surgery, finished fourth with 214.29 points. Takahashi stumbled on his opening quad toe loop and fell on two elements after that.
"I was a bit tired and nervous. My mental toughness was low," Takahashi said. "I need more practice to improve my stamina."
Ando, who won the Rostelecom Cup in Russia, landed six triple jumps in her routine to Cleopatra to finish with 162.55 points. Russia's Alena Leonova was second with 160.85, while Wagner was third with 155.99.
Wagner, who was first after the short program, touched down on a triple salchow and singled a triple lutz late in her routine to fall into third place.
China's Pang Qing and Tong Jian won the pairs event with 199.65 points followed by Russians Yuko Kavaguti and Alexander Smirnov with 193.05. Americans Rena Inoue and John Baldwin were third with 158.78.
