Nabil Fekir gave Les Gones an early lead but Layvin Kurzawa equalised on the stroke of half-time.
The drama continued after the interval, with Dani Alves being sent off before the hour and it fell to Memphis Depay to split the sides with a spectacular solo strike on 90 minutes.
Sunday’s win sees Bruno Genesio’s men close the gap in the title race down to eight points and Tousart hailed the way his team battled home, having spent most of the game without the ball.
“We are very happy with this result tonight even if it was not easy, against Paris it’s always complicated,” he said. “They have more the ball than us tonight but we managed to block, resist and make the round back at the right time in the game.
“We knew we would have the opportunities and we are rewarded tonight for all the work that the team provided. We were able to put the intensity that was needed and we emerged victorious tonight, we are very happy and satisfied.”
Uwe Rosler was sacked by Fleetwood following a 3-0 reverse at Doncaster which condemned Town to a seventh straight defeat in all competitions.
Cambridge interim head coach Joe Dunne was pleased with how his side adapted to beat Grimsby 3-1.
Southend manager Chris Powell led the applause for Jason Demetriou after the right-back scored twice in the 3-1 win against Portsmouth at Roots Hall.
Morecambe boss Jim Bentley was the happier manager after Gregg Wylde's 90th-minute strike earned his side a point in their 1-1 draw with Forest Green.
Manager Gareth Ainsworth described Wycombe's 2-0 win at Cheltenham as a thoroughly professional performance.
Skipper Richard Wood scored the winner just before half time as in-form Rotherham pulled off a 1-0 victory at League One leaders Shrewsbury.