Algeria's state prosecutor has requested four years in prison for Karim Tabbou, a key figure of anti-government protests, and the verdict has been set for March 11.
Tabbou's trial opened Wednesday in Algiers and continued until dawn as around 60 defence lawyers argued for his innocence, the prisoners' support group CNLD said.
The 46-year-old, who heads the small opposition party UDS, is accused of "inciting violence" and undermining "the morale" of the army, and has been detained since September.
Around 180 lawyers offered to defend him while some 100 supporters rallied outside the court on Wednesday demanding his release.
"Free Karim Tabbou and all the detainees," they chanted, before police dispersed them at night, according to witnesses.
Mass protests erupted in Algeria in February last year, in response to President Abdelaziz Bouteflika announcing he intended to run for a fifth term after 20 years in power -- despite being debilitated by a 2013 stroke.
Less than six weeks later, he stepped down after losing the support of the then-army chief in the face of enormous weekly demonstrations.
The arrests of protesters increased from June as the army toughened its line on the demonstrations, which have continued despite Bouteflika's exit and the election of a new president in December.
It is not clear how many are still being held, but in early February the CNLD had said that 142 members of the "Hirak" protest movement were in preventive detention.
Tabbou was considered one of the public faces and voices of the largely young and leaderless Hirak.