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.
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.
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.
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.
