Champions PSG were rarely troubled in their win at the Stade de la Route de Lorient and made it back-to-back successes in France's top flight.
Thiago Motta opened the scoring on 19 minutes with a superb curing effort that found the corner, as Laurent Blanc's men led 1-0 at half-time.
The visitors were awarded a penalty shortly after the restart when Blaise Matuidi was felled in the area by Cedric Hountondji. Sweden star Zlatan Ibrahimovic duly converted from 12 yards, taking his Ligue 1 tally to 14 for the campaign.
Forward Anthony Martial put Claudio Ranieri's men ahead on four minutes, and the visitors' situation improved further as full-back Jonathan Martins Pereira was shown a second yellow card.
Meanwhile, Nantes harbour ambitions of finishing in the top three and among the UEFA Champions League positions, but their hopes were dealt a blow in a 2-1 home defeat against Toulouse.
After a goalless first-half at the Stade de la Beaujoire, the visitors stole into a two-goal lead thanks to strikes from Etienne Didot and Jean-Daniel Akpa Akpro.
Papy Djilobodji halved the deficit in the 82nd minute, but Michel Der Zakarian's charges failed to find a leveller.
At the other end of the table, Sochaux's woes continued in a 1-0 defeat at Nice, who ended a seven-match losing streak in the process.
Fellow strugglers Ajaccio fell to a 2-1 defeat at home to Lorient, as Jeremie Aliadiere's strike made it five straight league victories for Christian Gourcuff's men.
Elsewhere, Floyd Ayite's injury-time leveller secured Reims a 1-1 draw at Evian.
