The 35-year-old bagged his side's only goal in the 1-1 draw with Strasbourg on State de la Meinau, securing a point which means second-placed Lens can no longer catch the Parisians.
PSG have been crowned champions of France in five of the last six seasons, however the talents of the likes of Messi, Neymar and Kylian Mbappe have been unable to steer the club to Champions League glory.
After Saturday's draw for PSG secured the title, Messi has now won 43 trophies in a glistening senior career - a tally which can only be matched by former Barcelona teammate Dani Alves.
The Argentinian has won four Champions League trophies, 12 league titles, seven association cups and most-notably the World Cup in 2022 after beating France in the final.
Messi's opener against Strasbourg on Saturday was his 496th in Europe's top five divisions, meaning he has overtaken Cristiano Ronaldo's record.