Hilton was leaving the new Bootsy Bellows nightclub on Sunset Blvd. with her old pal Brandon Davis and some other friends ... when a man in their group tried to pry a photog's camera out of his hands. An eyewitness tells us the photog tried to hit the dude with his camera.
During the struggle, Hilton -- wearing a tiny blue dress -- was knocked into a wall. She appeared to be OK ... and eventually left the parking structure.
Police were not called to the scene.
After the skirmish, the photog claims someone in Hilton's group took his camera and his jacket. He didn't say if he plans to follow up with police.