Tousart made his debut for the Ligue 2 side on 24 January 2015 against Tours. He played the whole match in a 2–1 home loss.[3]
Lyon
Tousart made his Lyon debut on 5 December 2015 in a Ligue 1 match against Angers. He was replaced by Clement Grenier after 61 minutes in a 2–0 home loss.[4]
He scored his first professional goal on 16 February 2017 in a UEFA Europa League game against Dutch side AZ Alkmaar, scoring the first goal in an eventual 4–1 victory.[5]
Hertha BSC
On 27 January 2020, Tousart signed with Bundesliga side Hertha BSC. He was however sent back to Lyon on loan until the end of the season.[6] While on loan to Lyon, Tousart volleyed in the game's only goal as Lyon shocked Juventus in the first leg of their Champions League Round of 16 tie.[7] It was announced in June 2020 that Tousart would join Hertha on 1 July, meaning that Tousart would be unable to take part in Lyon's postponed Champions League match following the COVID-19 pandemic.[8][9]
Union Berlin
On 19 July 2023, Tousart joined Hertha BSC's local rivals Union Berlin.[10] On 16 September 2023, he made his debut for the club in a 1–2 away loss to VfL Wolfsburg, coming on as a substitute in the second half.[11]