But the French champions stepped up a gear after the break to claim a no-nonsense win that lifted them to 50 points from 18 games, 13 ahead of second-placed Lille who have played two more games.
Uruguay striker Edinson Cavani bagged his 11th league goal this season when he converted a penalty in the 57th after Alexis Blin was sanctioned for handball.
PSG doubled the tally after Khaled Adenon was sent off following his second yellow card in the 66th minute.
In the 70th, striker Kylian Mbappe latched onto a cross from Cavani to give the visitors a two-goal cushion as he snatched his 14th goal of the season.
Centre back Marquinhos rounded it off 11 minutes from time as PSG continue their march towards the title, leaving Amiens in 17th place with 18 points.
Lille consolidated their second place on Friday by beating Caen 3-1 away as third-placed Olympique Lyonnais, who are four points behind the northerners, were held 1-1 at home by Stade de Reims.
Spanish midfielder Cesc Fabregas was named in the Monaco squad on Saturday, one day after joining from Chelsea as the struggling side coached by Thierry Henry face neighbours Olympique de Marseille at the Stade Velodrome on Sunday.
(Reporting by Julien Pretot, editing by Pritha Sarkar)
