A 20-year-old woman was sexually assaulted in Cowley Road.
Police said a man followed and then inappropriately touched the woman as she walked away from the city centre at about 2.30am on Saturday. She pushed him off before running away.
He is described as black or Asian, about 6ft and with short black hair. He was wearing a white hooded with a red zip. The inside of the hood was also red.
Police released details yesterday when they appealed for witnesses to call Pc Peter Watkins on 101.