It happened at the McDonalds on Blake Street in York between 3.35am and 3.50am on Saturday 27 November when a man in his 20s sustained serious head injuries.
He was taken by ambulance to the hospital for treatment before being discharged later that day.
Two people have been arrested in connection with the incident and released on police bail.
We are now asking anyone who recognises this man to get in touch as we believe he will have important information that will help our investigation.
If you know who he is or have any information that could help please email [email protected] or call North Yorkshire Police on 101, select option 2 and ask for Beth Williams.
If you wish to remain anonymous, you can pass information to Crimestoppers on 0800 555 111.
Please quote reference number 12210249748 when passing on information.
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