The incident happened during a disturbance involving several people in Market Buildings, at around 4am on New Year’s Day.
The victim, a man in his 20s, is alleged to have been assaulted with a weapon by a man he did not know.
He suffered cuts to his head and an ear, and was taken to hospital for medical attention.
PC Katie Poulter, of Maidstone CID, said: ‘We have been completing enquiries in the area, including the examination of CCTV footage, and are now releasing images of a person who may be able to assist with our enquiries.
‘While the images are blurred, we are hoping somebody will recognise him and call our appeal line.’
Anyone with information that may assist the investigation should call us on 01622 604100, quoting crime reference 46/216/22.
You can also call the independent charity Crimestoppers anonymously on 0800 555111 or complete the online form on their website at www.crimestoppers-uk.org