The woman, identified only as "Jane Doe" in the lawsuit against police, said she suffered anxiety and emotional distress.
The lawsuit says the woman provided information that helped police arrest Eric Julian, 26, of Fairfield last November on charges he tried to rape a 16-year-old girl while she was walking home from school.
"Despite being in fear of her life my client, a sexual assault victim, came forward and provided the Fairfield police with information to help their investigation after the officers promised to keep the information about her confidential," the woman's lawyer told the Connecticut Post. "But they broke their promise."
The woman said police promised her confidentiality, but then announced publicly that they received help from a woman Julian was charged with raping in 2002.
Fairfield's town attorney said police don't believe they did anything wrong because the woman had said she would be willing to testify against Julian.