Midfielder Leandro Paredes scored his first PSG goal before Mbappe's brace took his club career tally to 102 a few days before his 21st birthday.

Sunday's eventful game saw Neymar hold his head in his hands after a rare penalty miss, and the ultra-efficient Mauro Icardi scored yet another clinical goal.

In Lyon, star striker Memphis Depay and midfielder Jeff Reine-Adelaide were coming to terms with serious knee injuries that could keep them out for the rest of the season.

Both players ruptured knee ligaments during a 1-0 home defeat to fourth-place Rennes.

Saint-Etienne played 65 minutes with 10 men after midfielder Jean-Eudes Aholou's sending off.

It proved an easy win for Thomas Tuchel's side, who have played one game less than second-place Marseille approaching the mid-season winter break next weekend.

As Mbappe ran through and smacked the ball into the bottom left corner in the 90th, Saint-Etienne fans were in raucous party mode.

Flares were lit and fireworks let off.

The referee blew fulltime straight from the restart, choosing not to play any additional time.

He had interrupted the game for about a minute early in the second half to let smoke from flares dissipate.

Eduardo Camavinga scored an accomplished late goal as Rennes snatched a 1-0 win at Lyon to move up to fourth place.

The injuries to Depay and Reine-Adelaide overshadowed 17-year-old Camavinga's stellar performance as he celebrated his first league goal.

Rennes are one point behind third-place Lille, having played one game less, while Lyon slipped down to eighth spot after a second straight home defeat.

Lyon are in Monday's last-16 draw for the Champions League after securing qualification from Group G last week thanks to Depay's late equaliser against Leipzig.

Also Sunday, seventh-place Bordeaux lost 1-0 to mid-table Strasbourg.

Australian Associated Press