Detectives are investigating a serious assault in Northbridge last night.
About 2.20am, the 23-year-old male victim was walking with a friend along Roe Street in China Town when they were confronted by a group of men.
One of men argued with the victim (who speaks little English) before he punched him in the face.
The victim fell to the ground where the offender kicked him in the head.
The victim lost consciousness and the group of men ran towards the City of Perth car park.
The victim's friend confronted the offender shortly afterwards and was also assaulted with a skateboard he was carrying.
The victim's friend received minor injuries.
The victim was taken to Royal Perth Hospital and treated for a broken jaw and concussion.
The offender is described as dark skinned, between 20 and 25 years of age, short brown hair, medium build, wearing a red t-shirt, blue jeans and carrying a skateboard.
Information to Crime Stoppers 1800 333 000.