Lucas Moura's sixth goal of the season put the champions in front in the first half and Edinson Cavani sealed the points five minutes from time as Laurent Blanc's side maintained their unbeaten start to the campaign.
Having soaked up pressure from the visitors in the opening half hour, PSG took the lead when Lucas reached an Ezequiel Lavezzi cross to poke the ball beyond Steve Mandanda.
Chances were few and far between after the break, but the introduction of fit-again striker Zlatan Ibrahimovic, returning after a spell on the sidelines with a heel injury, gave PSG an extra spring in their step.
Gianelli Imbula's harsh late dismissal for a challenge on Yohan Cabaye all but ended Marcelo Bielsa's side's hopes of salvaging a point and Cavani added a second goal to ensure there was no way back for the leaders.
Marseille started on the front foot and had three chances to open the scoring in the first 10 minutes.
Two fell to Andre-Pierre Gignac, who first saw his header crash against the post and then curled a long-range effort wide of Salvatore Sirigu's goal.
Romain Alessandrini was unable to mark his recall to the starting line-up with an early goal, as he failed to convert a volley from the edge of the penalty area from a Benjamin Mendy cross.
PSG slowly found their feet and Mandanda was called into action for the first time, the goalkeeping saving at point-blank range from Javier Pastore after 21 minutes.
Sirigu continued to be the busier of the two goalkeepers, though, the Italian having to be alert to push away another Alessandrini effort on the half-hour mark.
Despite Marseille being in the ascendency for large parts of the half it was the hosts who broke the deadlock 38 minutes in, when Lavezzi delivered a low cross into the penalty area and Lucas beat Mendy to poke the ball home.
Seven minutes after the break Gignac had his third chance of the match after pressurising the PSG defence, but his attempted chip over Sirigu did not have enough height on it, allowing the keeper to claim easily.
Lucas' pace was beginning to threaten the Marseille defence as the game became stretched, however the Brazilian's final ball and finishing let him down in promising positions.
Ibrahimovic made his return from injury in the 65th minute, and within two minutes he was in the thick of the action.
The Sweden striker carried the ball towards the Marseille penalty area before finding Lucas, who in turn laid the ball off to Cabaye and the midfielder saw his low shot pushed away by Mandanda with Cavani unable to finish following up.
Marseille's chances of getting anything out of the game looked slim when Imbula was harshly shown a straight red card for a challenge on Cabaye.
And Cavani secured the win for PSG with five minutes to play, when the Uruguay strike rose to convert Serge Aurier's right-wing cross.
