A total of 401 people had been put on trial in a prison 60 miles from the capital Ndjamena, a trial which lawyers had boycotted citing that it did not follow the law.
Of those who were not sentenced to prison, 80 received a suspended sentence and 59 were released.
According to public reports, around 50 people were killed when police opened fire on protesters in the capital N’Djamena and other towns.
However, opposition groups say the actual death toll is much higher. The victims were unarmed civilians.