On Sunday, six members of the Salafist movement were arrested after they stormed a cinema and broke its glass doors in a bid to stop the screening of the film: "Neither Allah, nor Master" on secularism in Tunisia.
The cinema raid prompted outcry from several corners of Tunisian society.
On Tuesday, about 100 Salafist demonstrators gathered outside the main courthouse in Tunis to protest against the weekend arrests, chanting: "God is great" and other slogans.
Demanding the six men be released, they attacked three lawyers who had to be taken to hospital.
Police intervened and arrested about thirty people, according to multiple sources.
On Monday, Tunisia's Islamist movement Ennahda (Renaissance) said it had pulled out of a national commission tasked with drawing up political reforms.
The group, which was legalised early March after three decades as a banned opposition group, accused the panel of ignoring the true aims of Tunisians.
After years in political exile, some believe Tunisia's hardline Islamist groups can play a leading role in the country's future as it emerges from a popular uprising that forced president Zine el Abidine Ben Ali to flee after 23 years in power.