Polanski is already facing charges for having sex with a 13-year-old girl in 1977.
Lewis' claims comes amid US authorities' efforts to get the director extradited from Switzerland to face the court in connection with the earlier case.
Addressing a news conference in LA, Lewis said, "Mr Polanski knew that I was only 16 years old when he met me and forced himself upon me in his apartment in Paris."
"He took advantage of me and I have lived with the effects of his behavior ever since it occurred," she added.
76-year-old accused was arrested in Switzerland in Sep 2009 after he fled US in 1978. Before leaving California, Polanski had pleaded guilty to unlawful sex with a minor. But he left before being formally sentenced.