Marquinhos bundled home the opener shortly before half-time at the Parc des Princes to cap a strong first-half performance.
Uruguay international Edinson Cavani then scored his fourth goal of the season from the penalty spot to secure the three points for Blanc's side.
And the former France boss said finding the breakthrough before the interval was the catalyst for victory against a strong Toulouse outfit.
"We expected to find a well-consolidated and well-organised team," he told the club's official website.
"This is what happened. As often happens when you score it unlocks the game.
"The opposing team takes more risks. It took a long time to score the second goal, but we succeeded."
Forward Jeremy Menez made his return from a long lay-off after undergoing surgery for a herniated disc in July.
And the Frenchman was delighted to be playing first-team football again.
"It feels good to be back on the field," he added. "It was four and a half months since I last started a game. So it was fun, especially to end with victory.
"Physically, I'm still a bit short, but you find your rhythm by playing."
