A man was left with a broken cheek bone following an attack in Crawley town centre on Saturday.
Police say they were called to the High Street at around 2.40am after the man was punched in the face and left with serious injuries.
As well as suffering a broken cheek bone, the victim - a man in his 30s - was also suffered two other facial fractures and was taken to hospital for treatment.
Police say that a 29-year-old man from Crawley was later arrested on suspicion of grievous bodily harm with intent and has been released under investigation.
Anyone who witnessed the assault is asked to report it online or call 101 quoting reference 153 of 05/05, visit the Crimestoppers website or contact the independent charity anonymously on 0800 555 111.