A man reportedly attacked a parking attendant in Market Rasen when he issued him with a ticket.
Lincolnshire Police said the assault took place on Deer Street at around 10.45am on Friday, March 6.
The suspect is also believed to have verbally abused the attendant, who walked away with a minor injury to his chest.
Police say they are looking for a man in his 20s with short dark hair who was clean-shaven, wearing a grey hooded top and blue jeans.
Anyone with information has been urged to call 101 and quote incident 130 of March 6.