France striker Mbappe found the back of the net with a jaw-dropping backheel finish early in the second half and Neymar doubled the tally in the closing stages to put PSG on 36 points from 15 games.
Second-placed Marseille, who have played one game more, had narrowed the gap to two points with a 2-0 victory at Angers on Tuesday.
Elsewhere, St Etienne climbed up to fifth on 25 points with a 4-1 home win over Nice.
(Reporting by Julien Pretot; Editing by Ed Osmond)
Day 4, Sheffield
Evening Session, Day 4
First Session, Day 4
Second Session, Day 4