The visitors came from behind to claim victory, but due to Montpellier's win against Auxerre, will finish the season as runners up
It looked as though the season was going to end ignominiously for Carlo Ancelotti's side when Kevin Monnet-Paquet put the hosts ahead. However, after the break, Javier Pastore and Thiago Motta managed to turn the game on its head, although MHSC's win over Auxerre denied the capital club the title.
PSG went into the match knowing that they had to win if they were to stand any chance of title glory, and hope that already-relegated Auxerre could pull off a surprise victory against Montpellier.
Lorient were also in dire need of points in order to ensure their top-flight status for another season, but the early exchanges were of a cautious nature, with neither side seeming to be willing to commit too many men forward.
Gradually, however, the Breton side began to creep forward; a volley of early crosses were scrambled away by the Parisian defence, while the Lorient midfield were quick to smother each PSG player when they were in possession.
Lorient were looking incisive. Joel Campbell had already bent a beautiful free kick narrowly wide when Monnet-Paquet slid in at the far post to turn a Lucas Mareque cross past Salvatore Sirigu, and into the net.
Falling behind only managed to rouse the static Parisians. Javier Pastore bounded clear of the Lorient defence, but could only drive a shot against Jeremie Janot's legs, before the Argentine scooped a shot over the bar after receiving a Kevin Gameiro ball on the penalty spot.
However, just as they were beginning to look threatening, their momentum was killed when a disgruntled PSG fan threw a flare on to the pitch, causing a five-minute break in play.
When the match eventually restarted, it was Lorient who began looked more threatening, and Sirigu stopped Joel Campbell from doubling their lead when the Arsenal loanee met Mathieu Coutadeur's free kick.
After the break, things didn't look as though they were going to get any better for the visitors. Pastore miscued another effort, looping the ball well over the bar, before Guillaume Hoarau brilliantly brought down a high ball, turned his man, but dragged his shot wide when he should have scored.
However, they soon found a way through the stern Lorient defence. Pastore initially headed Christophe Jallet's cross, but managed to prod the ball into the net when the rebound fell favourably to him.
Their hard work was almost undone immediately in the cruelest fashion, though. Campbell collected the ball 30 yards from goal, and smashed an effort goalwards that almost looped over the helpless Sirigu after a hefty deflection.
Campbell tested the former Palermo keeper yet again with a quarter of an hour remaining, before PSG got a crucial goal. Nene swung in a corner from the right wing, and Motta was there to head it home.
Mathieu Bodmer almost added a third, but nodded Pastore's cross just wide, and the miss made no difference. PSG had won, but due to Montpellier's win against Auxerre, their title bid came to an end.
Meanwhile, despite losing, Lorient will be a Ligue 1 club next season due to results elsewhere.