The ruling against Judge Bechir Akremi came after President Kais Saied pledged to lead a campaign against widespread corruption.
It also came a day after Saied said he “would not turn into a dictator” after the arrest of two MPs on Friday over his decision to lift their immunity when he took control of the government this week. .
Tunisia was plunged into a political crisis by Saied’s decision on Sunday to sack the prime minister and suspend parliament for 30 days, leading major parties to accuse him of a coup.
Saied has yet to take the steps critics say are necessary to reassure Tunisians, including appointing an interim prime minister and a roadmap to end emergency measures.
“I know the constitutional texts very well, I respect them and I have taught them and after all this time I will not turn into a dictator as some have said,” said the presidency, quoting the former law professor.
On Sunday, Saied lifted the immunity of members of parliament, leaving all cases against them subject to arrest.
Concerns about rights and freedoms in Tunisia, a democracy since the 2011 revolution, rose on Friday after the arrest of parliamentarian and influential blogger Yassin Ayari and the announcement of investigations into allegations of violence by people protesting against Saied’s actions during a protest on Monday.
Military justice said Ayari was jailed by a court ruling issued three years ago for defaming the military.
Ayari has spoken out against the military and the government and has encountered legal problems in the past.
Another deputy, Maher Zid of the Karama party, was arrested on Friday evening, according to his lawyer.
He was sentenced to two years in prison in 2018 for offending people on social media and insulting the then president.
On Monday, the largest party in parliament, Ennahdha, staged a sit-in outside parliament after being surrounded by the military.
Hundreds of Ennahdha and Saied supporters clashed, some throwing stones and bottles.
Justice said it had opened investigations into four people linked to Ennahdha for “attempting to commit acts of violence” during the demonstration, including a member of a party council and two members with links to its leader.
Ennahdha has been a key player in Tunisia’s legislative elections since the 2011 revolution, which sparked the Arab Spring uprisings across the region.
Saied’s decision to take control of the executive appears to have broad popular support in Tunisia, where years of poor governance, corruption, political paralysis and economic stagnation have been compounded this year by a deadly increase in cases of COVID-19.