Police say the alleged assault happened shortly before 22:30 on Saturday night by the Adelphi Lounge in Gloucester Street.
Police said that the reported victim was wearing a light-coloured “smart shirt” and had short brown hair, while the suspect, who was arrested at the scene, was wearing a dark-coloured top and shorts, also with short brown hair.
Pictured: The altercation happened outside the Adelphi in St. Helier.
He was also said to have had a bicycle with him.
A young female with a pram was said to be present at the time of the brawl.
Police are now seeking more information on what happened, and are urging islanders who witnessed the incident to call 612612 or make an anonymous report using Crimestoppers’ online form.