The defending Ligue 1 champions went into the game having lost only one league game all season. And Laurent Blanc's men rarely looked in danger of succumbing to defeat at the Stade de Route de Lorient as the capital club clinched only their second win in 12 league visits to Rennes.
Midfielder Thiago Motta put PSG in front with a fine effort from distance before Zlatan Ibrahimovic doubled his side's advantage, the Swede taking his tally for the season to 22 with a second-half penalty.
Winger Romain Alessandrini did pull one back for the hosts, but Edinson Cavani added a third late on as PSG racked up a 13th league win of the season.
Ibrahimovic returned to Blanc's starting XI after being left out of PSG's 2-1 UEFA Champions League defeat against Benfica on Tuesday, while Jean-Armel Kana-Biyik replaced suspended former PSG centre-back Sylvain Armand in the Rennes defence.
The visitors started the brighter of the two sides, Ibrahimovic shooting just wide from a free-kick in the opening stages.
PSG duly took the lead with an opener in spectacular fashion after 19 minutes when Motta curled a wonderful strike into the bottom corner.
Blanc's men dictated the play in an opening period of few chances, although Rennes remained a threat on the counter-attack, with Kana-Biyik heading wide from a corner just after the half-hour mark.
Kana-Biyik narrowly missed the target again minutes before half-time as they pushed for the equaliser.
But the Brittany club's task was made considerably harder shortly after the interval when Ibrahimovic converted from 12 yards following Cedric Hountondji's foul on Blaise Matuidi.
PSG dominated proceedings throughout, although Rennes were given hope after 67 minutes, Alessandrini's low free-kick flying under Salvatore Sirigu and into the bottom corner.
The hosts, however, were never able to exert any sustained pressure on PSG, whose victory was confirmed in the final minute of injury time as Cavani powered a shot past Benoit Costil following a quick counter-attack.
Blanc's PSG are now likely to head into the mid-season break as league leaders as they bid to follow in the footsteps of the likes of Lyon and Marseille by winning back-to-back top-flight titles in France.
