Ghannouchi, 81, has been in prison since April. His lawyer said the charges stem from a funeral eulogy he gave last year for a member of his Ennahda party when he said the deceased "did not fear a ruler or tyrant, he only feared God."
The leader of the Islamist Ennahda party is also accused of plotting against state security along with other detained opposition figures who accuse Saied of a coup for shutting down the elected parliament and moving to rule by decree.
Saied, who enshrined his new powers in a constitution that he passed through a referendum with low turnout last year, has denied his actions were a coup and said they were needed to save Tunisia from years of chaos.
He has called his critics criminals, traitors and terrorists and warned that any judge who freed them would be considered abetting them.
Ghannouchi has refused to appear before judges in legal cases, arguing that the charges are fabricated and the trial is political, his lawyer said.
"These trials are the purification against opposition leaders, using the judiciary, because they have not been able to defeat them politically," said Bouali.
Ghannouchi, a political prisoner and exile before the 2011 revolution that brought democracy, was parliament speaker from the 2019 election until Saied sent tanks to shut down the chamber in 2021.
Tunisian authorities last month banned meetings at all Ennahda offices and police closed the headquarters of the Salvation Front, the main opposition coalition, in what rights groups called a de facto ban.
The Tunisian authorities did not comment on the decision, but Saied said that "no one is above the law" and that he will not back down from holding accountable those who have committed crimes against the country.
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