The world number one, bidding to win the Paris indoor title for an unprecedented third time in a row, broke to love in the last game of the opening set, playing tighter when it mattered.
He broke again in the eighth game of the second set as Bellucci sent a forehand long and closed out the match on serve to snatch his fifth win against Bellucci in as many encounters.
“The last match I played indoors was last year in London. So that’s why it’s always tricky to start out well,” Djokovic told a news conference.
“I have had a few things that I could have done better tonight. But again, all in all, it was a very solid match.
“I played against a player who was in form and who is playing well and gave me a hard time.. it’s always good to have a test like this.”
Top seed Djokovic, who already has three Paris Masters titles to his name, next faces a Frenchman, 14th seed Gilles Simon or Benoit Paire.
Earlier, Stan Wawrinka started his Paris Masters challenge with a 6-3 7-6(6) win over Australian Bernard Tomic after surviving a blip in the tiebreak to reach the third round.
The world number four from Switzerland trailed 5-2 in the tiebreak but raised his game to close out the match in straight sets at a renovated Bercy Hall.
“I was not in a good position, that’s for sure,” said Wawrinka, who is bidding to become the first player to win the French Open and Paris Masters in the same year since Andre Agassi in 1999.
“I played one good point, aggressive, then he missed an easy forehand, and you’re back,” he told a news conference.
Wawrinka next faces either Spanish 15th seed Feliciano Lopez or Serbian Viktor Troicki.
Spanish eighth seed David Ferrer also reached the third round when he swept aside Alexandr Dolgopolov of Ukraine 6-2 6-2.
The Paris Masters is the last tournament before the season-ending ATP World Tour finals, which will be played between the eight best players of the season from Nov. 15-22 at the 02 arena in London.
Djokovic, Wawrinka, Roger Federer, Rafa Nadal, Kei Nishikori, Andy Murray, Tomas Berdych and Ferrer have all qualified.
(Editing by Ed Osmond and Ken Ferris)