Katy Perry -- Krackdown on Katy Krap

Katy Perry is surrounded by fakes, frauds and counterfeits ... according to a new lawsuit.

Bravado International -- which licenses the exclusive right to hawk T-shirts, hats, posters and other crap from the likes of Michael Jackson, the Red Hot Chili Peppers, The Rolling Stones, The Doors, Guns N' Roses and Led Zeppelin -- is now targeting Katy kounterfitters.

According to court docs, the frauds are selling illegal Katy merchandise outside her concerts and they want a judge to stop them in their tracks ... and confiscate all the bad stuff.

Bravado has gone after counterfeiters before ... to scare them and clean up the streets.