Roger Federer was beaten 5-7, 5-7 on the opening day after Novak Djokovic had swatted aside debutant Matteo Berrettini in the earlier Group Bjorn Borg contest.
Novak Djokovic saw off the challenge of Matteo Berrettini in just 64 minutes, converting five of seven break points and out-serving his 23-year-old opponent.
The "Big Three" remain the men to beat at the season-ending ATP Finals in London.
Rafael Nadal, who has never won the ATP Finals despite his trophy-laden career, dethroned Novak Djokovic from the top of the rankings this week.
Novak Djokovic and Roger Federer were drawn in the same group for next week's climax to the season, the ATP Finals.
Novak Djokovic has now won 34 Masters titles, moving to within one of Rafael Nadal at the top of the all-time list, and 77 on the ATP Tour in total.
Rafael Nadal will take over from Novak Djokovic at the top of the world rankings next week, despite missing out on the chance to win a maiden title at Bercy.
Top seed Novak Djokovic came through a dramatic first-set tie-break before prevailing 7-6 (7/5), 6-4 to move to the brink of a record-extending fifth Bercy title.
Rafael Nadal is bidding for a record-extending 36th Masters crown and will take on Denis Shapovalov in the last four.
Novak Djokovic holds an 8-1 winning head-to-head record against Grigor Dimitrov, who saw off unseeded Chilean Cristian Garin 6-2, 7-5 earlier in the day.
Paris Masters: Rafael Nadal produced an impressive display to take his career head-to-head record against three-time Grand Slam champion Stan Wawrinka to 19-3.
Novak Djokovic saw off Britain's Kyle Edmund to reach quarterfinals while Grigor Dimitrov knocked out fifth seed Dominic Thiem in Paris Masters.
Rafael Nadal beat France's Adrian Mannarino 7-5, 6-4 while Novak Djokovic won his match against Corentin Moutet 7-6 (7/2), 6-4.
Novak Djokovic and Rafael Nadal put their immediate aims to one side and played a practice session in Paris.
Roger Federer said he was withdrawing from this week's Paris Masters in order to "pace" himself for the next year.
Roger Federer is third in the world rankings, while Rafael Nadal and Novak Djokovic won all four Grand Slams between them this year.
Roger Federer, who has won a doubles gold alongside fellow Swiss Stan Wawrinka, is still waiting to get his hands on an Olympic singles gold.