Tuchel led PSG to the Champions League final four months ago as PSG rounded off 2020 with a routine 4-0 win over Strasbourg in Ligue 1 on Wednesday through goals from Timothee Pembele, Kylian Mbappe, Idrissa Gueye and Moise Kean.
Tuchel masterminded back-to-back Ligue 1 title triumphs after he was appointed in May 2018, also winning the Coupe de France, Coupe de la Ligue and claiming the Trophee des Champions twice.
PSG missed out on a maiden Champions League success when they were beaten 1-0 by Bayern Munich in the final in August.
Tuchel endured a fractious relationship with sporting director Leonardo, but the Brazilian last month stated that the club had never considered sacking the former Borussia Dortmund head coach.
Criticism of PSG's lack of transfer business from Tuchel, whose contract was due to expire at the end of this season, did not go down well with Leonardo during the previous window.
PSG lost their first two Ligue 1 matches of the campaign amid a coronavirus outbreak and Tuchel then suggested a repeat of the 2019-20 campaign could not be expected due to a lack of investment in the playing squad.
Despite a less than vintage start domestically, Tuchel guided last year's runners-up into the Champions League round of 16 as Group H winners.
His replacement will do battle with Barcelona for a place in the quarter-finals.