Mischa Barton -- My Mother's a Financial Vampire ... She's Sucking Me Dry

Mischa Barton's mother/manager pocketed a chunk of her daughter's salary from a movie -- and even kicked Mischa out of her own Beverly Hills mansion ... according to a new lawsuit.

Mischa filed the suit against her mom, Nuala Barton ... claiming she's a "greedy stage mother posing as a talent manager" ... and says she lied to Mischa about her income on a film called "The Hoarder." In the docs, Mischa says Nuala told her she was being paid a certain amount ... but eventually found out from the production company her salary was higher than that number.

She says Nuala took the difference for herself ... and also took a 10% management fee. She doesn't mention specific numbers in the lawsuit.

Mischa says mommie dearest also used her name to pimp out a handbag line and to open a Mischa Barton fashion boutique in London -- all of which might have been great if Mischa got a dime from any of it. She says Nuala kept all the profits for herself.

As for Mischa's home -- she says her mother rigged the paperwork to give herself co-ownership of the 8 bedroom, 11 bath mansion. According to the suit, Nuala even took out loans against the property -- and then kicked her out of her own home. She says her mom and dad are now "comfortably" entrenched in the mansion.

The suit gets particularly nasty ... with Mischa stating her parents "sit back expecting their daughter's hard work and dedication to her craft to support their lifestyle." She adds neither of them has had a job, outside of Mischa Inc., in over a decade.