The league leaders were on top from the off, with Presnel Kimpembe firing straight at Alban Lafont from close range on five minutes and Angel Di Maria dipping a left-footed effort just wide of the target.
PSG continued to threaten but Toulouse mustered a dangerous chance of their own on the quarter-hour mark, Yaya Sanogo connecting with a cross to head goalwards, only for Alphonse Areola to claim at the second attempt.
Neither side could break the deadlock come half time, but PSG eventually found the breakthrough on 68 minutes as Neymar got the better of Steeve Yago before rifling the ball off the nearby Issa Diop and past Lafont.
The visitors went close to adding a second late on, but Neymar rifled a shot against the post before lofting a curling effort onto the top of the crossbar.
The result sees PSG move 13 points clear at the top of the Ligue 1 table, while Toulouse remain 15th in the standings.
TOULOUSE (4-3-3): Lafont, Yago, Diop, Amian, Sylla, Cahuzac, Blin, Imbula, Jean (Mubele 74'), Gradel, Sanogo (Delort 77')
PARIS SAINT-GERMAIN (4-3-3): Areola, Alves, Kimpembe, Marquinhos, Berchiche, Rabiot (Pastore 71'), Diarra (Verratti 61'), Lo Celso, Di Maria (Draxler 71'), Mbappe, Neymar