The government of Tunisian President Zine el-Abidine Ben Ali came to an end last month after waves of protesters complained his regime wasn't doing enough to usher in democratic and economic reform.
The United Nations said hundreds of people were killed during the political unrest that led to Ben Ali fleeing to Saudi Arabia. Human Rights Watch said its representatives saw uniformed officers beating civilians and assaulting French journalists last week.
Sarah Leah Whitson, the director of Middle East and North African affairs at Human Rights Watch, said in a statement the transitional government needs to keep things under control.
"The government should make clear that officers who violently abuse people will be punished," she said.
Human Rights Watch called on Tunisian Interior Minister Farhat Rajhi to issue clear orders to security forces to respect the new-found freedom of assembly in the country.
"This brutality heightens tensions and shows that the police continue to act as if they are above the law, despite Ben Ali's departure," added Whitson.