With a crucial UEFA Champions League quarter-final against Liverpool FC approaching, manager Luis Enrique rotated his squad, leaving key figures on the bench. Despite that, PSG started brightly.
Khvicha Kvaratskhelia tested goalkeeper Guillaume Restes early on, but it was Dembele who made the breakthrough. After Achraf Hakimi's cross was only partially cleared, the forward struck a superb first-time volley to open the scoring.
Toulouse responded quickly. Rasmus Nicolaisen equalised with a powerful header after a costly misjudgement from PSG goalkeeper Matvey Safonov.
PSG regained control before the break. Dembele struck again, reacting sharply at close range after a flick-on from Kvaratskhelia to score his 10th league goal of the season.
The second half saw PSG manage the game with patience. Dembele thought he had completed his hat-trick, only for the goal to be ruled out for offside. Chances followed, with Joao Neves firing wide and both Willian Pacho and Illia Zabarnyi denied by Restes.
Toulouse rarely threatened, although another Safonov error nearly gifted an opportunity to Aron Donnum, whose effort drifted wide.
PSG sealed the win in stoppage time when Goncalo Ramos finished calmly to make it 3-1.
After the match, Enrique praised his side's focus, saying: "I'm very happy. We knew how important these three points were, especially after the international break. It's always difficult because many players had travelled and played matches."
He added: "We had one less day's rest, but the team showed its ability to handle the match. Now it's time to rest, especially mentally, and prepare for Liverpool."
Enrique also highlighted Hakimi's leadership on the night: "It's a pleasure to see a player like Hakimi. He was captain today and showed his level and his ability to lift the team."
PSG now turn their attention to their European challenge, while Toulouse remain stuck in mid-table after missing the chance to build further momentum.
