'Shahs Of Sunset' Slammed By Hot Model ... I'm the REAL 'Persian Barbie'

There can only be one "PERSIAN BARBIE" ... so says a smokin' hot model who claims Bravo's show "Shahs of Sunset" is illegally using HER moniker for one of their cast members.

Niki Ghazian (left) -- FHM model and self-proclaimed "Persian Barbie" -- fired off a cease and desist letter last week to Bravo honchos ... claiming the network has no right to use the term for its newest star Lilly Ghalichi (right).

FYI -- Lilly's co-stars refer to her as the "Persian Barbie" on the show ... which Bravo has utilized in promos and on Lilly's official bio.

Niki says that's not okay -- and while she never applied for a trademark, she says she's the "common law owner" ... claiming ever since 2005, publications like FHM, Kandy Mag, NYLA Mag and more have used it to describe her.