The hosts were a long way from their sparkling best and were arguably fortunate to be level at the break after a first half in which Edinson Cavani had a penalty saved and Troyes had a goal ruled out for the narrowest of offsides.
PSG were little better after the break, but the talismanic Neymar settled the match 17 minutes from time as he found the corner of the net from 20 yards.
He then put the ball on a plate for Cavani to double the lead in the 90th minute and add gloss to the scoreline.
Angel Di Maria was the sharpest man on the pitch in the early stages as he saw an effort saved and another whistle just wide in the first 20 minutes.
But those were PSG's best two efforts in the first half from open play.
On the half hour, Kevin Trapp was forced to make a decent save after a tricky run from Samuel Grandsir, and the 21-year-old then had the ball in the net six minutes later only for the goal to be disallowed.
The main talking point of the opening half came six minutes from the break when Cavani went down in the box under a slight shirt tug from Karim Azamoum and the referee pointed to the spot.
The Uruguayan stepped up to take the penalty with the Parc des Princes shouting his name, but his powerful effort was kept out by Mamadou Samassa.
Neymar was kept relatively quiet by Troyes, limited to a spectacular rabona cross that came to nothing, per French football writer Jonathan Johnson:
The visitors were well-organised and looked dangerous at times on the counter, but the deadlock was finally broken when Neymar tucked an excellent finish into the corner after carving out a bit of space just outside the box.
The Brazilian superstar was then released down the left with a long ball in the final minute of normal time.
He checked back effectively and squared to the onrushing Cavani, who took a touch and drove home from 12 yards to ensure PSG moved 10 points clear at the top of Ligue 1.