Trivedi, 25, an activist of India Against Corruption, was picked up Saturday evening by Mumbai police from Bandra-Kurla following a non-bailable arrest warrant issued against him.
He is accused of uploading "ugly and obscene" matter on his web portal and for putting up objectionable banners insulting the Indian constitution during Anna Hazare's anti-corruption agitation here last December.
He was presented before a magistrate Sunday and remanded to police custody for questioning, an IAC spokesperson said.
Trivedi faces sedition charges under Section 124A of the Indian Penal Code, among other offences under the Information Technology Act.
An IAC spokesperson claimed that police did not allow them to meet Trivedi when they went to meet him in the lock-up in the morning to discuss his defence procedures.
"Even in the court, they (police) did not allow the IAC people to meet him and in fact they roughed up and bluffed IAC volunteers who had gathered in support of Trivedi outside the court," the spokesperson said.
The IAC alleged Trivedi "was badly roughed up and pushed into the police vehicle where his head banged against the vehicle body".
"We are shocked at the way an artist and activist is being treated by police. The IAC Mumbai will always support freedom of expression which is the right of every individual given to us by the constitution," the IAC said.