A man suffered a broken jaw in an attack near Micklegate Bar in York.
He was punched to the ground during the assault which happened in the early hours of Saturday.
The man was walking along a footpath between York Cabs and the Subway shop in Blossom Street at around 2.50am when he was attacked.
His attacker then fled the scene.
Anyone who witnessed the assault is asked to call North Yorkshire Police on 101, quoting reference 12190015411.