Filner, who will resign his seat Friday after 20 women came forward alleging he fondled them, demeaned them and made unwanted sexual advances, has admitted "personal failures" have embarrassed the city but has denied he ever sexually harassed the women.
Stacy McKenzie, a parks manager who's worked for the city for 32 years, said Filner came on to her while she was working and asked her for a date. She turned him down and days later McKenzie said Filner approached her again, putting her in a headlock and groping her breasts.
Dan Gilleon, McKenzie's lawyer, said he will file a notice of claim with the city, a precursor to a filing a lawsuit.
U-T San Diego said if McKenzie follows through with her lawsuit threat it would be the first instance of a woman suing the city over Filner's alleged behavior.
He is being sued personally by his former communications director who said she, too, was subjected to sexual harassment while working for Filner.
Filner announced he plans to step down Friday and addressed the city after six weeks of intense scrutiny.
"The city should not have been put through this," Filner said during his resignation speech. "And my own personal failures were responsible."