Luis Enrique's troops missed out on the chance to clinch the title on Saturday with a 3-3 draw at home to Le Havre, but that six-goal stalemate only delayed their coronation.
Monaco started the day 12 points adrift of the capital giants and needed to triumph at the Groupama Stadium to stand the slimmest chance of dethroning the champions, and their quest began perfectly as Wissam Ben Yedder opened the scoring inside 30 seconds.
However, Pierre Sage's men turned the tie on its head before the break as Alexandre Lacazette and Said Benrahma found the net, but Ben Yedder's second of the night on the hour mark gave Les Monegasques hope of their own comeback.
The Monaco talisman thought he had completed his hat-trick in the 78th minute, but he had just gone a fraction too early from a free kick, and the visitors' fleeting title chances were officially extinguished when Malick Fofana finished off a sweeping counter-attack with six minutes of normal time remaining.
As Lyon revelled in their comeback triumph, PSG celebrated their record-extending 12th top-flight coronation, and Les Parisiens have now won three straight titles since briefly ceding their accolade to Lille in 2020-21.
PSG have now added two honours to their trophy cabinet already this season, having also defeated Toulouse in the Trophee des Champions, and they will face Lyon in the final of the Coupe de France on May 25.
Enrique's side are also going in search of Champions League glory this season, travelling to Borussia Dortmund for the first leg of their semi-final on Wednesday evening.