The 18-year-old victim was set upon after he left Edinburgh's Castle Club at around 3am on Saturday September 15.
He was approached by a group of three men on Queensferry Street, who attacked him and gave him a broken nose and a laceration to his cheek, police said.
The victim is described as black, 6ft 2ins and of slim build. He was wearing a grey suit, black shirt and a white trilby hat.
The suspects are all said to be white men, around 5ft 8ins tall, between 18 to 25 years old and with skinny, athletic builds. One was wearing a purple t-shirt and the other two were wearing white or grey t-shirts.
Detective Constable Joe Perkins, of Police Scotland, said: "The street was pretty busy at this time so we are appealing for anyone who may have witnessed this assault on Queensferry Street to come forward. Similarly if anyone recognises the description of the suspects then they should contact police."
Police Scotland can be contacted on 101.