Led by the film co-producer Manik Mandal, around 15 people including some from Nandigram, were protesting outside the Netaji Indoor Stadium when they were arrested.
However, said they were later released.
The film producer Sarfaraz Alam told PTI that he is shocked by the behaviour of the police as well as the decision of the film festival authorities for rejecting the film, which has been screened at various other festivals including Berlin and Mumbai film festivals.
"This is a film from the heart of Bengal and is based on true story. So we do not know why the festival went against the film. They were just protesting peacefully when the police picked them up," Alam said.