The assault happened at the Cellar nightclub in Cornmarket Street at about 12.30am on Saturday 20 September this year.
A member of staff, a woman aged 33, asked a customer to leave the club.
The customer, a woman, then assaulted the member of staff by slapping her to the head.
Investigating officer, PC David Stagg based at Cowley police station, said: “The victim has been left with a perforated ear drum, which may result in permanent loss of hearing.
“I am releasing CCTV of a woman, who may have vital information about the incident.
“If you are the woman in the images, or know who she is, please contact the police immediately.
“You can call 101, visit a police station or go online to https://www.thamesvalley.police.uk/tua/tell-us-about/cor/tell-us-about-existing-case-report/ quoting investigation number 43180293338.”