The defending champions had lost on their last four visits to the Stade de la Route de Lorient, but Thiago Motta gave them a half-time lead which was extended by Zlatan Ibrahimovic from the penalty spot early in the second half.
Romain Alessandrini then gave the home crowd hope of a comeback with his free-kick, but Edinson Cavani's strike in the final minute wrapped up PSG's sixth victory in seven league matches.
Nearest challengers Monaco enjoyed a routine 2-0 win away to 10-man Guingamp.
Anthony Martial put the principality club ahead early on and after Jonathan Martins-Pereira was sent off for a second bookable offence, Layvin Kurzawa headed in Joao Moutinho's corner to make the points safe before half-time.
Fourth-placed Nantes were beaten 2-1 at home by Toulouse, who extended their unbeaten run to four games.
Second-half goals from Etienne Didot and Jean Daniel Akpa Akpro were enough for Le Tefece despite Nantes defender Papy Djilobodji's deflected long-range strike.
Lorient made it five wins in a row, beating Ajaccio 2-1 to leave their opponents firmly entrenched in the relegation zone.
Vincent Aboubakar's opener for the visitors was cancelled out Salim Arrache before the interval, but Jeremie Aliadiere's strike proved decisive as Lorient continued to move the right way up the standings.
Ajaccio, however, have not won in the league since the end of September - a run of 11 matches - and lie seven points from safety with only Sochaux keeping them off the bottom.
A solitary goal by Eric Bautheac was enough for Nice to bring to an end seven successive defeats as they claimed a 1-0 win over Sochaux.
Bautheac slotted home between the legs of goalkeeper Pierrick Cros after 23 minutes to condemn Les Lionceaux to their fourth consecutive loss and leave them rooted to the bottom of the table.
Floyd Ayite's injury-time goal earned Reims a point at Evian and denied their opponents a victory which would have moved them further clear of the bottom three.
The home side, who beat title hopefuls PSG last time out, had taken the lead 16 minutes from time through Jonathan Mensah's powerful shot.