A 21-year-old man required hospital treatment after the attack near the Stag Bar on Weavers Close on Thursday 22 December.
Police Scotland has released images of a man they wish to trace in connection with the incident.
They have asked him or anyone who might know him to come forward to assist with their inquiries.
He has been described as a black male, aged between 25 and 35 years old with short, dark hair, dark facial hair or a beard.
At the time of the incident, he was wearing a two-tone hooded anorak, dark trousers and dark footwear.
He was seen in the vicinity of the incident and also subsequently in the Townhouse Hotel.
It is believed that he may have links to the Liverpool or Manchester area.
Police have released CCTV images as part of investigations into an assault outside an Arbroath bar last year.