Laurent Blanc's champions extended their Ligue 1 benchmark point total to 89 with a 27th triumph this term - the most victories ever recorded in a French top-flight season.
Montpellier, league winners in 2012 but uncomfortably close to the relegation places this term, could not repeat the heroics displayed in January's 2-1 Coupe de France win at the Parc des Princes, which denied PSG a tilt at the domestic treble.
But the league and Coupe de la Ligue crowns are stowed for safe keeping in the French capital, with Friday's confirmation of punishments for breaching UEFA's Financial Fair Play rules never likely to dampen the festivities.
Before kick-off, PSG president Nasser al-Khelaifi insisted the decision from European football's governing body would not check his ambitious plans for the club and Ezequiel Lavezzi tapped into the optimism with a second-minute opener.
Talisman Zlatan Ibrahimovic extended his club-record haul to 41 goals from the season before further goals from Lucas Moura and Adrien Rabiot completed the rout.
There was understandably a party atmosphere inside the Parc des Princes and the home faithful soon had something to shout about.
Geoffrey Jourdren punched clear unconvincingly when Ibrahimovic chipped into his six-yard box and PSG kept the attack alive, enabling Lavezzi to poach an opener from close range.
The Argentinian attacker sniffed a second when Jourdren grasped an Ibrahimovic drive at the second attempt, while Montpellier's goalkeeper was rooted to the spot when Lucas' deflected long-range effort cannoned back off the crossbar.
Marquinhos showed no signs of the disappointment he suffered in missing out on a place in Brazil’s FIFA World Cup squad last week, producing a fine block to deny Benjamin Stambouli as Montpellier threatened for the first time.
PSG doubled their advantage in the 20th minute as Ibrahimovic sprung the offside trap to convert Javier Pastore's beautifully flighted pass.
Montpellier pressed gamely and the home defence had to remain on its mettle, but this approach left holes for PSG to exploit and an offside flag was required to chalk off a clinical Lavezzi finish in the 34th minute.
Lavezzi should have had a second before the interval but headed over from Lucas Digne's sumptuous cross, while a Jourdren double save thwarted Lucas Moura and the former Napoli forward.
The third duly arrived four minutes after the restart when Lucas bravely opted to ignore a poised Ibrahimovic and drill beyond Jourdren at his near post.
Thiago Motta joined an attack to blaze over in the 61st minute and shortly afterwards Ibrahimovic and Lavezzi were withdrawn to standing ovations.
There was a testimonial feel thereafter - heightened when home full-back Christophe Jallet was denied a rare goal by another fine Jourdren save - but there was still time for Rabiot to put the seal on a season that will live long in the memory for his club's fans.
The midfielder made the most of an empty net in the 88th minute after substitute Kingsley Coman saw his shot squirm from Jourdren's grasp
