This is the club's seventh Ligue 1 title, and it now sits 17 points ahead of Monaco in second-winning the league with five games to spare.
A stunning six-minute spell in the first half put PSG in complete control as they scored three times through Giovani Lo Celso, Edinson Cavani and Angel Di Maria, before former got his second of the day and the team's 100th this season just before the half-hour mark.
That proved to be the final goal of the match as PSG secured the league title in emphatic fashion against last season's winners.
But a second successive last 16 exit in the Champions League means heads will roll at the end of this season in preparation for another attempt to muscle in among Europe's elite.
Although luck was on Monaco's side early on when Cavani missed a glorious opportunity, PSG were playing with a ruthlessness that was not going to see them slip up.
Kamil Glik's absence in the heart of the visiting defence was acutely felt as Lo Celso started the move that resulted in the opening goal on 14 minutes, sauntering into the box to tap in a Dani Alves cross.
But PSG continued to attack at will and Pastore's nonchalant assist for Di Maria allowed the winger to grab his second of the game on 59 minutes.
Javier Pastore supplied Lo Celso to head in PSG's fourth on 28 minutes and Monaco suffered further misfortune when France global Djibril Sidibe was stretchered off with a leg injury, a worrying sign for Didier Deschamps ahead of the World Cup.
Thousands say emotional goodbye to 'Mama Winnie' at funeral service
In 1977, she was uprooted from her Soweto home and placed under house arrest for eight years in a small town, Brandfort. President Cyril Ramaphosa is sitting next to the two daughters of Madikizela-Mandela and Nelson Mandela.
Monaco pulled one back, Lopes latching on to Almamy Toure's cross from the right to score for the eighth consecutive time in Ligue 1 - a first in the French top flight since Shabani Nonda in 2003.
PSG's best goal came from Di Maria, who scored yet another delightful chip.
Julian Draxler rounded off the scoring for PSG in the 86th minute, with German attacker turning home Thomas Munier's cross.
- Paris have won their seventh Ligue 1 title.
They joined Lyon in fifth place in the rankings of the clubs with the most French titles - three behind record holders St Etienne.
- Unai Emery has won his first top-flight title. The usual front three of Di Maria, Cavani and Neymar left teams for dead on numerous occasions with the front three scoring a total of 55 goals in Ligue 1 this season.
In a display of ruthless efficiency, PSG showcased the disparity between themselves and the rest of the competition by racing into a 4-1 lead at the break.