More than 150 people have surrounded a Sydney police station to protest against the treatment of sandwich board activist Danny Lim after footage of him being arrested sent social media into a frenzy.
The cult Sydney personality is now considering legal action against police.
The former local councillor was fined on Friday after three police officers arrested him at Exchange Place in Barangaroo about 9.20am.
It's unclear what the offensive behaviour involved or who made the complaint though one woman, on Facebook, admitted she called the police because Mr Lim was "in the way" and "disturbing".
Protesters have gathered to rally against what they say is the brutal arrest of well known Sydney activist Danny Lim. Source: AAP
Video of the arrest shows an officer holding a sandwich board sign that reads: "SMILE CVN'T! WHY CVN'T?".
Social media was quickly flooded with calls for a protest against the police after Mr Lim released images of his bruised wrists following Friday's arrest.
Mr Lim told social media he had been left distressed after his companion dog, Smarty, was also caught up in the arrest.
Crowds converged on the CBD's police station after midday on Sunday.
Many carried signs with inverted A symbols including "STOP CORRUPT GOVERNMENT CVNTS".
Mr Lim, wearing a large sign calling on politicians to act on chemical contaminations, thanked the crowd and those who had recorded his arrest on their phones.
"I couldn't thank them enough," he said.
"I asked for help, help, I told them I had to pick up my dog Smarty."
Mr Lim says he has PTSD but urged people to "have a heart" and fight injustice for their children and grandchildren.
"The biggest injury which everyone must be able to take is when they try to break you, your mind, your heart, don't let them do it," he said.
His lawyer, Bryan Wrench, told the crowd the pair would not tolerate "political censorship".
"The only thing offensive was how they treated Danny on that day, and Smarty," he said.
"We are not going to let this go. We are going to fight all the way."
Mr Wrench represented Mr Lim in 2017 when a District Court judge overturned a conviction and fine after finding a similar sign worn in 2015 mocking then-prime minister Tony Abbott was unlikely to offend the average Australian.
The protesters outside Sydney City Police Area Command. Source: AAP
Using an inverted A in the word "can't", those signs said "TONY YOU CAN'T. LIAR, HEARTLESS, CRUEL" and "TONY YOU CAN'T SCREW EDUCATION."
Mr Wrench said they would repeat history.
"We did it before and we are going to do it again," he said.
"And this time they're going to pay. We'll see you when we go to court. And they can't stop us - C V N T."
A GoFundMe has been started up to raise $500 for Mr Lim's court costs following his arrest.
By Sunday afternoon it had almost tripled its goal and raised $1300.
