Teresa Yuan entered her plea Friday in Brooklyn federal court. Prosecutors allege Yuan sent 504 emails and 120 webcam videos of herself to a Cotillard fan website over a period of four days in 2011.
In some of the videos, which were shown in court, Yuan appears topless, hisses like a cat and talks about playing Russian roulette. Her lawyer admitted the videos could appear to be threatening.
According to the Daily News, the 32-year-old Queens resident told a judge that she is undergoing psychiatric treatment for bipolar disorder.
Yuan faces up to 16 months in prison, but her lawyer says prosecutors have indicated they wouldn't object to probation and psychological treatment.
The Associated Press contributed to this report.