Mauricio Pochettino’s men were given a helping hand by a nightmarish display from Lille goalkeeper Ivo Grbic at the Stade Pierre-Mauroy.
Portuguese midfielder Danilo Pereira netted twice, while Presnel Kimpembe also got on the scoresheet.
All eyes in the capital remain on Paris’ Champions League last-16 first leg against Real Madrid on February 15.
Mbappe, who has long been linked with Real, said that match has been the reason he is yet to make a decision about his future, despite having been free to sign a pre-contract agreement with another club since the start of last month.
“Playing against Real Madrid changes a lot of things,” the World Cup winner told Amazon Prime.
“Even if I’m free to do what I want, I’m not going to talk to the opponents. I’m focused on winning against Real Madrid and we’ll see what happens afterwards.”
This game, though, was the perfect response for PSG after their French Cup exit on penalties at the hands of Nice in midweek.
Lille are languishing down in 11th place after a seventh defeat of their title defence.
The hosts needed to get something from the game to move into the top half of the table, but they made a calamitous start.
Grbic somehow failed to gather in Nuno Mendes’ low cross despite being under no pressure, and Danilo duly stabbed into an empty net to give PSG a 10th-minute lead.
Hatem Ben Arfa, making his first start since last April after his surprise move to Lille, set up Sven Botman to equalise before the half-hour mark.
But PSG were back in front in the 32nd minute as Grbic totally missed Messi’s corner and Kimpembe bundled home from close range.
Messi grabbed his first goal of 2022 in slightly fortuitous circumstances, as a clearance ricocheted of his shins and played him in on goal.
Grbic rushed out to close the angle, but the seven-time Ballon d’Or winner coolly dinked the ball into the net to score his second Ligue 1 goal.
“I have never had any doubts about Messi,” said PSG coach Pochettino. “He’s the best player in the world.
“He was spectacular. I’m happy with his performance.”
PSG quickly put paid to any thoughts of a second-half comeback from Lille as Danilo scored his second goal.
The 26-year-old Grbic’s day took another turn for the worse as he followed a fumble with a poor clearance, which Leandro Paredes squared for Danilo to fire a long-range effort into the bottom corner.
There was nothing the goalkeeper could do to keep about PSG’s fifth goal midway through the second half, though, as Mbappe unleashed a magnificent, curling strike from outside the area into the top corner.
Earlier on Sunday, Nice missed the chance to retake second place in the table from Marseille as they slumped to a 1-0 home defeat by struggling Clermont.
Rennes then took advantage, beating Brest 2-0 to move up to fifth, just five points behind Nice in the third and final Champions League spot.
Bordeaux’s dreadful season continued as they dropped into the bottom two after an embarrassing 5-0 thrashing at Reims.