Refugees have been subject to "unprovoked and extreme violence and bullying" by French police officers in Calais, including beatings and destruction of belongings, according to the Refugee Rights Data Project (RRDP) report.
“A number of accounts appear to suggest that police violence .... sometimes takes disproportionate and life-threatening forms," it states.
A year on from the demolition of the notorious Calais Jungle, the number of displaced people still in the area is estimated at 2,000.
RRDP interviewed 223 refugees around the Calais area for this report, published on Monday.
They found that the methods of intimidation and violence were often unconventional, including spraying sleeping bags with tear gas so that they could no longer be used and the confiscation of shoes.
A 16-year-old Eritrean boy told researchers of witnessing a baton attack so sustained he thought the victim would be killed.
In another account, a 17-year-old Eritrean girl told how police detained her, then drove her to a remote location at 6.00pm, abandoning her to walk three hours back to Calais. She told researchers she felt scared as it was dark and she did not know the way.
Tear gas in her face
Separately, a 25-year-old woman in Calais told researchers she saw another woman of her age being sprayed with tear gas by police.
“There were two policemen surrounding her. She turned away from the one in front and the one behind sprayed her in the face,” she said.
“They sprayed for a long time and then when she turned away the one in front of her sprayed her in the face also. After the second spray she fell over, when she got up they sprayed again. She ran for about 15 minutes but couldn’t see anything."
The child refugees also told of 4.00am police raids that, according to them, always involved tear gas or pepper spray, with most saying their sleeping bags were sprayed to make them unusable.
“The police "spray tear gas in my face," a 16-year-old boy from Afghanistan said. "They take my blanket, sometimes my shoes, then they beat us with sticks and we run away.”
Many reported having their shoes confiscated and having to run away barefoot in the wet and cold.
Other testimonies reveal refugees have been held for long periods of time in the local police station, with one family saying they were detained for an entire day, during which time they were given no food or clean nappies for their young baby.
Of those questioned, nine out of 10 said they did not feel safe in Calais and the same proportion said they had experienced police violence.
When confronted with the new allegations by the UK's Independent newspaper, the Calais regional authority referred to Interior Minister Gérard Collomb's earlier order to police chiefs in the region to remind officers of the regulations they must comply with, especially while dismantling unofficial camps.