A former advisor to Tunisian President Moncef Marzouki was handed a four-month suspended jail term for defaming the army and its commanders, he said on Saturday.
"We will launch an appeal as soon as possible against this charade," Ayoub Messaoudi told AFP.
He went on trial in August behind closed doors before a military court on charges of defaming Tunisia's army, the chief of staff, Rachid Ammar, and Defence Minister Abdelkarim Zbidi.
Rights group heavily questioned the chances of a fair trail as the army itself was judging the case. Messaoudi could have faced up to five years behind bars.
Messaoudi had accused Ammar and Zbidi in a television broadcast in July of "treason" for not having informed President Moncef Marzouki in advance of the extradition of former Libyan premier Baghdadi al-Mahmudi to Tripoli.
Prime Minister Hamadi Jebali ordered the transfer at the end of June, causing a political crisis within Tunisia's ruling coalition, led by Jebali's moderate Islamist Ennahda party.
Marzouki, who belongs to the centre-left Congress for the Republic, was furious with the decision, having always expressed doubts about the ability of the new Libyan regime to guarantee Moamer Kadhafi's last premier a fair trial.