With a crucial final game of the UEFA Champions League coming up next week, PSG manager Thomas Tuchel left out Neymar out of the squad and rested Kylian Mbappe on the bench. Meanwhile, Bafana Bafana winger Keagan Dolly was named on the home side's bench.
Florent Mollet had the first chance for Montpellier on the half-hour mark after latching onto a loose ball just outside the box but his powerful strike was saved by goalkeeper Keylor Navas.
However, Colin Dagba broke the deadlock for the Parisians three minutes later with a left-footed strike just outside the six-yard box after a cut-back by Di Maria on the byline.
Stephy Mavididi levelled matters for the hosts just before the break with a close range strike after his initial effort was blocked on the line by Dagba, with the referee indicating that the goal had crossed the line after confirmation by goal-line technology.
PSG pressurised Montpellier in the early stages of the second stanza and Di Maria came the closest to restoring their lead in the last 22 minutes after curling a strike towards the far post but goalkeeper Jonas Omlin made a great save.
Kean eventually restored the lead for Tuchel's charges 13 minutes before time with a smashing strike at the near post after a through ball by Rafinha.
Teji Savanier came close to snatching the equaliser for the hosts in the last seven minutes with a free-kick from the edge of the box that missed slightly over the bar.
Late substitute Mbappe sealed the three points for PSG with their third goal in stoppage time with a tap-in after a cut-back by Layvin Kurzawa.