Of the 73 protesters arrested after storming the US embassy in Tunis last September, a judge convicted 20 and released them with two-year suspended sentences.
A lawyer representing some of the accused told The Associated Press that a judge convicted them on Tuesday night.
Four protesters died during an attack carried out by thousands on the embassy and a nearby American School, Agence France-Presse said.
Lawyer Slah Barakati called the proceedings a show trial for Americans and Europeans.
“These protests were part of a spontaneous reaction throughout the (Muslim) world against attacks on our sacred symbols,” he said, according to AFP.
Police opened fire on the crowd, in which Reuters said demonstrators set fire to the buildings, stole computers and threw rocks at police.
The attacks came in reaction to a low-budget American movie that Muslims said denigrated the Prophet Mohammad.
The film was made in California and posted online.
It was a similar attack in Benghazi, Libya, a few days earlier that ended with the death of US Ambassador Chris Stevens and three of his staff.
Tunis has tried to balance ties with the US and controlling radical Islamists since 2011.
It was then Tunisians overthrew longtime strongman Zine El Abidine Ben Ali, triggering the Arab Spring.
The country now needs an estimated $2.5 billion to kick-start its economy, Reuters said, and is looking to the US for aid.
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