But Mr Polanski's lawyer told London's High Court that the director had been "monstrously libelled for the sake of a lurid anecdote".
Mr Polanski is suing over claims he made sexual advances to a woman shortly after his wife was murdered in 1969.
Vanity Fair magazine denies libelling Mr Polanski in the July 2002 article.
Timing of incident
The article said Mr Polanski made advances to "Swedish beauty" Beatte Telle in New York restaurant Elaine's shortly after the death of his wife, Sharon Tate.
The magazine has since accepted the incident did not happen when Mr Polanski was on his way back to Hollywood for Ms Tate's funeral, but said it occurred about two weeks later.
Ms Tate was murdered by Charles Manson's "family" at the couple's home in Bel Air, California.
Mr Polanski won the right to testify from Paris, amid fears that if he entered the UK he would face extradition to the US, where he is still required to face child sex charges.
"This law knows of no rules - only violations of civilised conduct which, it appears, can be readily excused."
He said the magazine's case was that Mr Polanski was "well capable of behaving badly" by the end of August 1969.
Mr Shields said the fact that Mr Polanski had casual sex within a month of his wife's death revealed a "certain callous indifference" to her memory.
He went on: "An honourable man would come to this court, an honourable man would return to California, an honourable man would not behave the way he behaved - even in the Swinging Sixties."
Mr Shields added: "These matters are not minor blemishes on his reputation. They are scars which can never be healed."
He urged the jury that even if his defence failed, he should not be entitled to any damages and the jury should give Mr Polanski "a symbolic award", such as "the price of a cinema ticket".
"By that symbolic award, you can send a message across the Channel about the moral values which decent people cherish."
Mr Polanski's lawyer, John Kelsey-Fry said the director had been in "utter grief" after his wife's death, not - as the defence team claimed - "utter indifference".
"The truth is that Mr Polanski was about as removed from callous indifference as is possible to imagine," Mr Kelsey-Fry said.
He said that at a press conference on 19 August 1969, it had been an "inescapable fact" that Mr Polanski was not indifferent to his wife's name and memory, "but precisely the contrary".
"He was at pains - and I mean obvious pain - to honour it, protect it and defend it," Mr Kelsey-Fry said.
"The burden is on the defence to prove their case. The most obvious witness to call if their case is true, and she supports it, is Beatte Telle," he added. "You have heard not one word of evidence from her."
In summing up, Mr Justice Eady told the jury that "much has been made of Mr Polanski's lifestyle and his attitude towards casual sex in his earlier years".
But he said it was important to remember that it was not a "court of morals", adding: "We are not here to judge Mr Polanski's personal lifestyle."
Telling them that an "absolute maximum ceiling" of £200,000 in damages could be awarded, he sent the jury out to begin their deliberations.
The case was adjourned until Friday.