Three of the men have been put under house arrest, two from Rome and one living in Marghera, north-east Italy, while another is currently in a district prison in Ferrara.
One of the protesters, named only by the initials MC, 22, is believed to have used a slingshot to hurl objects at riot police during the April 12th protest. He was wearing ski goggles and a gas mask at the time, La Repubblica reported.
The anti-government march descended into chaos outside the Ministry for Industry, on Rome’s Via Veneto, with protesters clashing with riot police.
Twenty police officers were reported injured at the time, while Italian media this week said 60 were seen by medics. One protester was seriously injured when a firecracker reportedly went off in his hand.
Organizers said 15,000 people took part in the initially peaceful protest, calling on the government to take action on a number of issues including housing and job creation.