Laurent Blanc's side sat third heading into the weekend, level on points with Marseille and two behind leaders Lyon, after dropping points against Caen last time out.
Despite missing a host of key names, PSG banished the demons of last weekend's 2-2 draw, when they squandered a 2-0 lead, to claim a vital three points.
Adrien Rabiot scored either side of half-time for the hosts, both following good work from Javier Pastore.
Alain Casanova started with top scorer Wissam Ben Yedder on the bench, but the striker came on before half-time and pulled one back three minutes after Rabiot's second.
PSG responded in positive fashion, unlike the previous week, and Thiago Silva added a third 16 minutes from time to send the champions top, at least until their rivals are in action on Sunday.
The build-up to this match had been dominated by Blanc's shortage of options, with the manager claiming to have only 13 outfield players to pick from.
It appeared his side were low on ideas too, until Pastore injected some much-needed pace into PSG's attack to create the opener in the 27th minute.
The Argentinian skipped away from a couple of challenges in midfield before spreading the ball wide and continuing his run to collect and square for Zlatan Ibrahimovic to backheel into the path of Rabiot, who curled a wonderful left-footed shot into the far corner from 20 yards with his team's first effort on target.
It should have been quickly followed by a second, but Silva steered his downward header wide when left unmarked from a corner two minutes later.
Toulouse almost levelled with their first meaningful attack four minutes before half-time but Salvatore Sirigu did well to turn Abel Aguilar's header behind following a flowing counter-attack started by the quick feet of Jean-Daniel Akpa-Akpro.
Casanova's side were denied the chance to build on a strong finish to the first half as Rabiot scored his second on 48 minutes.
Again Pastore was the creator, wriggling out of a hole on the right-hand side before driving into the box to drill a low ball across for Rabiot to force over the line from a yard out.
The two-goal cushion lasted just three minutes as Ben Yedder profited from slack defending to nod in from close range - taking his season tally to eight.
Edinson Cavani went close to adding a third in the 58th minute, firing off target but Silva made no such mistake in the 74th, as he flicked Jean-Christophe Bahebeck's whipped free-kick past Ali Ahamada to settle PSG nerves.
In contrast to last week, PSG saw out the closing stages with minimal fuss to secure an important win, which should breed confidence among Blanc's squad.
