Guernsey Police have said it happened on St. George’s Esplanade at around 01:15 on Saturday 25 August 2018.
A group of people are alleged to have been involved in the incident, which took place between the Foresters Arms and Salerie corner and which left a man with facial injuries.
Guernsey Police said they’d like to speak to anyone that may have witnessed the assault and anyone with information should contact PC 97 Du Port on 725111 or Crimestoppers on 0800 555 111.