Police are appealing for witnesses after the incident outside The Crown Inn, High Street, Selsey in the early hours of Sunday, March 15.
A police spokesperson said: "The victim was among a crowd of people who left The Crown Inn after the pub closed.
"He was assaulted and sustained a broken jaw and had to undergo surgery the following day at St Richards Hospital."
A 27-year-old man from Chichester voluntarily attended a police interview on March 18, police said.
Officers have spoken to a 'number of witnesses' and would like to hear from anyone who saw what happened or who has any information that could assist with the investigation.
Anyone with information is asked to report it online or call 101, quoting serial 71 of 15/03.
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