Perth pair attacked after man 'moons' car

Two people have been assaulted after they followed a group of men who "mooned" them in Perth's entertainment district.

The woman and her male passenger, both 39, were driving in Northbridge when four men stepped onto the road, forcing them to brake before one of the men banged on the car, pulled down his pants and showed his buttocks.

They parked the car, followed the group and were attacked, with the man knocked unconscious and the woman sustaining serious facial injuries.

A 27-year-old man has been charged with grievous bodily harm and will appear before Perth Magistrates Court on December 4 while a 21-year-old man will face a charge of common assault in court at a later date.