Allyson Is Watching (1998)

Allyson is a small-town girl who dreams of becoming a big star. Arriving in Hollywood, she takes a new apartment and is warned by the landlord about a bad-girl resident named Bridget. This pricks Allyson's interest, and she soon finds herself spying on Bridget's outrageous sexual exploits. Naturally, she starts off watching, but she's soon joining in herself.