The offensive behaviour case against a prominent Sydney activist has prompted a court to examine the advertising of fashion giant French Connection.

Key points: Danny Lim was arrested at Barangaroo in January and fined $500 for offensive behaviour over his sandwich board sign

Danny Lim was arrested at Barangaroo in January and fined $500 for offensive behaviour over his sandwich board sign His lawyer Bryan Wrench today compared Mr Lim's sign to advertising by UK brand French Connection

His lawyer Bryan Wrench today compared Mr Lim's sign to advertising by UK brand French Connection In 2017 a District Court judge overturned a fine and conviction over a similar sign worn by Mr Lim

Danny Lim, 75, is well known around the CBD for his sandwich boards which often target politicians and include a play on words.

He was arrested at Barangaroo in January and fined $500 for offensive behaviour for wearing a sign that read: "Smile cvn't! Why cvn't?".

Mr Lim is contesting the fine in Sydney's Downing Centre Local Court, where his lawyer Bryan Wrench today compared the double entendre to French Connection UK's advertising.

"It's my fashionista coming out, your honour," Mr Wrench said while cross-examining one of the arresting officers.

Mr Wrench showed Detective Senior Constable Tufan Salman a photo of a large shop sign that read "FCUK".

"Could that sign also be interpreted as f***? Mr Wrench asked.

"It could be," the policeman replied.

Mr Wrench said advertisers often used attention-grabbing methods to promote their products.

Senior Constable Salman insisted he interpreted Mr Lim's sign to be hinting at what he said was a far more offensive word.

Witnesses 'social justice idiots'

Mr Lim has previously had overturned a conviction and fine which were imposed after he wore a similar sign that referred to former prime minister Tony Abbott and used the word "cvn't".

In 2017, a District Court judge found the earlier sign was in poor taste but not offensive, citing the "impugned word" in question as being prevalent in everyday language, particularly in Australia.

The court was played body-worn camera footage in which Mr Lim told police his hand hurt after being arrested, and one officer replied he was "bullshitting".

In the vision, witnesses could be heard describing the arrest as "disgusting" and "unbelievable" and were told to move on.

One officer is also heard describing the witnesses as "f***ing pathetic".

"They're all the social justice idiots. 'Oh my God … police brutality'," he said.

The officer said if Mr Lim had not "carried on" the way he did, he would not have been in handcuffs.

Police told Mr Lim they had received "a number of complaints" about the sign, which was taken from him as evidence.

But the court heard the arrest was triggered by a single complaint from a woman who was walking to work at Barangaroo and called a nearby police station.

When asked how offended she was, she replied: "As a woman, I found this word highly offensive."

The prosecutor said comparing Mr Lim's sign with French Connection's use of "FCUK" in advertising was "comparing apples and oranges", and told the court it was school holidays and the Barangaroo area was very busy.