LOS ANGELES (KABC) -- A woman arrested for going topless at a Bernie Sanders rally was going after the city of Los Angeles and the L.A. Police Department with a lawsuit claiming officers roughed her up.

Anni Ma was taken into custody by LAPD officers during the rally in March and refused orders to cover up.

Ma said the officers used excessive force while arresting her.

"They twisted my arm, pushed me on the ground and put their knees on my back, put me in jail for 25 hours," Ma said.

The woman was charged with indecent exposure, accused of violating a penal code regarding exposure of private parts in a public place.

"Breasts, by law, are not genitals, therefore, indecent exposure was not an appropriate charge," said Allen Baylis, Ma's attorney.

Now, her attorney filed a federal lawsuit against the city and the police department, claiming, among other things, that Ma's freedom of speech rights were violated.

"A political rally is the one place where the First Amendment protection is the highest. So their arrest stopped her from exercising her First Amendment rights," Baylis added.

Ma said she has taken her top off at several events over the last year and a half as part of a movement she calls "free the nipple."

"...to destigmatize women's bodies, and because it's so hyper-sexualized, I want to point out that I'm existing in a non-sexual position where many people don't get to see that very often," Ma added.