Constitution is first since the ousting of President Zine el-Abidine Ben Ali three years ago.
Celebration comes as constitution nears completion.
Latest step in political struggle for the birthplace of the Arab Spring.
Since the assassination of left-wing politician in July, country has been plunged into a crisis
Ennahda has agreed to step down following negotiations with opposition parties next week.
Zied el-Heni alleged to have defamed a civil servant in egging case.
Ruling Islamists have agreed to an initiative by the country's main labor union.
Ali Larayedh made clear government will ignore demands to step down.
Mohammed Brahmi, an Arab nationalist , was killed in his car outside his home.
Amina Tyler may be charged for 'provocative acts' at site of slated hardline Islamist conference.
