UPDATE 1-RBC sued by trader who dated alleged Ponzi schemer

*Plaintiff dated hedge fund manager later accused of fraud

*RBC says plaintiff showed poor judgment (Adds ages, details from complaint)

NEW YORK, Sept 21 (Reuters) - A top-performing female trader has sued RBC Capital Markets for gender bias over her dismissal, which she said stemmed from her dating a hedge fund manager later charged with fraud for running a Ponzi scheme.

In a lawsuit filed late Friday with the U.S. District Court in Manhattan, the trader, Lindy Boville, accused RBC of using her relationship with James Nicholson as a pretext to fire her in March 2009 and assign her accounts to male workers, some of whom subjected her to sexually charged advances and comments.

The Toronto resident, who had worked in RBC’s New York office, said she dated Nicholson on and off between March 2008 and February 2009 but had no business dealings with him.

She said male colleagues who did work with Nicholson were not punished by RBC, a unit of Royal Bank of Canada RY.TO.

Nicholson ran Westgate Capital Management LLC in Pearl River, New York, prior to his Feb. 25 arrest. A grand jury in April indicted him for fraud for running an alleged Ponzi scheme since 2004 that caused $150 million of investor losses.

Boville said RBC later filed a termination notice that falsely said she “showed poor judgment in financing efforts for hedge fund.” This notice has made it hard for her to find a new job and caused one employment offer to be rescinded, she said.

In response to the lawsuit, RBC spokesman Kevin Foster said in an e-mail: “Ms. Boville showed poor judgment in helping Jim Nicholson raise money for his hedge fund and failing to disclose her activities to her supervisors. It is irrelevant that she had a personal relationship with Nicholson, and she should have told RBC what she was doing.”

A lawyer for Nicholson did not immediately return a call seeking a comment. Nicholson was 42 at the time of his indictment. Boville is 33, her lawyer said.

The lawsuit said Boville joined RBC in September 2007 after being heavily recruited by the Canadian bank and by Goldman Sachs Group Inc GS.N.

It said she received the highest rating on her 2008 review, after her $7 million to $8 million of commissions made her one of her group’s top revenue producers.

Nonetheless, it said RBC on March 16 told her she was fired because it had “lost confidence” in her in light of her “personal association with Mr. Nicholson.”

The lawsuit also said that prior to being fired, Boville was subjected to repeated advances and graphic comments about her appearance by male RBC colleagues.

She accused one co-worker of making comments about her legs, such as, “Did that dress shrink at the dry cleaners?” She accused another of using the made-up word “sensy” rather than “sexy” so that RBC’s monitoring system would not pick up his language.

Boville is seeking to recover lost pay and benefits, compensatory and punitive damages and other remedies.

The case is Boville v. RBC Capital Markets Corp, U.S. District Court, Southern District of New York (Manhattan), No. 09-8016. (Reporting by Jonathan Stempel; editing by John Wallace)