Thomas Tuchel’s side, who face Manchester United in the second leg of their Champions League last-16 tie on Wednesday, were denied by the woodwork on three occasions during the first half, while Caen striker Enzo Crivelli also saw a header come back off the crossbar.
Ninga put Caen in front when he volleyed home the ball in a well-worked set-piece routine but PSG went level three minutes later after Younn Zahary conceded a penalty for handball that Mbappe dispatched.
Angel Di Maria came close to putting PSG in front when he headed off the post from close range minutes later, but Mbappe sealed the points with a tap-in after Thomas Meunier’s shot was blocked by a defender on the line but fell into the path of the striker.
The result leaves PSG on 71 points at the summit of Ligue 1, 20 clear of second-placed Lille, while Caen remain deep in relegation trouble in 18th place, four points adrift of safety.
(Writing by Alasdair Mackenzie; editing by Clare Fallon)
