Kean started at the Parc des Princes and scored a first-half brace, his first goals since moving to PSG on loan from Everton.
Mbappe then replaced the Italy international in the latter stages and added a late double of his own as Thomas Tuchel’s team — for whom Neymar was outstanding — bounced back from their midweek Champions League loss to Manchester United and made it six consecutive Ligue 1 victories.
The result allowed PSG to go top of the table, a point clear of Lille, although the northerners can reclaim first place by beating Nice on Sunday.
“The most important thing was to get back to winning ways at home,” captain Marquinhos told Canal+.
“We know this season is not going to be easy. We are going to have lots of matches, we rotated the team here but we were still competitive on the field.”
The reigning champions were missing nine players due to injury or suspension, including Angel di Maria and Marco Verratti, while Mbappe was rested at kick-off ahead of a trip to Turkey to play Istanbul Basaksehir on Wednesday.
In a game played behind closed doors in the French capital because of the health crisis, Kean came in and converted a Mitchel Bakker cross to open the scoring in the third minute.
Neymar then headed against the post before setting up Kean’s second goal midway through the first half.
Released on the counter-attack by Julian Draxler, Neymar ran half the length of the field with the ball before leaving Kean with an easy finish.
PSG lost Draxler to injury in the second half before Mbappe replaced Kean and ran onto a Neymar pass to make it 3-0 eight minutes from time.
In the 88th minute Neymar produced a lovely pass to pick out Pablo Sarabia, who teed up Mbappe to seal the win.
Marseille won 1-0 at Lorient earlier with a second-half goal from Argentine defender Leonardo Balerdi moving them up to fourth just behind Rennes, who lost 2-1 to Angers on Friday.
Andre Villas-Boas’s side host Manchester City in the Champions League on Tuesday.
‘Health situation takes priority’
Lens’ home clash with Nantes scheduled for Sunday was called off after they lost the equivalent of a whole team to positive coronavirus tests.
In a statement, the French league (LFP) said that “noting the certain absence of 11 Lens players from a list of 30 because of positive RT-PCR tests…it has decided to postpone the game between Lens and Nantes scheduled for Sunday to a later date”.
Lens did not confirm the identity of the players concerned, but local newspaper La Voix du Nord reported that two staff members, including coach Franck Haise, were also positive.
“The health situation takes priority but this changes a lot of things for the league itself,” said the Nantes coach, Christian Gourcuff, whose squad had already travelled to Lens.
“I think that what we have experienced is going to happen again.”
It is not the first time this season a Ligue 1 game has been postponed due to Covid-19. Marseille’s meeting with Bordeaux on the opening night of the campaign in August was rescheduled for the same reason.
After that, and fearing an avalanche of postponements, the LFP relaxed its health protocol to ensure games could go ahead as long as at least 20 players from a list of 30 on each team tested negative.
The Ligue 2 game between Grenoble and Nancy scheduled for Saturday was also postponed after 13 Grenoble players tested positive along with five staff members.
Lens and its surrounding region, in far northern France, are currently under a nighttime curfew along with much of the country as part of efforts to reduce the spread of the virus.
France has recorded more than one million cases and close to 35,000 deaths from Covid-19.