A 26-year-old man was attacked outside a furniture store at Banbury Cross Retail Park.
Thames Valley Police said there was an altercation between two drivers in the car park outside Benson for Beds at about 3.25pm on August 30.
Officers said the attacker got out of his car before approaching the victim, who was sitting in his car at the Lockhead Close shopping centre.
The force said he then punched the victim in his face.
Police added the attacker, who was believed to be in his late 40s or early 50s, was a white man about 6ft with light brown hair.
Investigating officer, PC Beth Cocker based at Banbury Police Station, said: “The area was very busy with bank holiday shoppers and a large amount of foot and vehicle traffic."
Thames Valley Police only released information about the incident today.
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