A skateboarder who was attacked on Friday, June 21, between 2.25pm and 2.30pm, in Market Square, Wellingborough, is being asked to come forward by police.
An eyewitness saw a young male riding a skateboard along the road by the taxi rank.
The driver of a car, which was behind the skateboarder, was seen to try and knock him off his skateboard.
The skateboarder jumped off onto the pavement at which point the driver got out of the car, grabbed him and punched him.
The victim ran off and the driver got back into his car.
Officers are keen to speak with the victim, who has not come forward.
The offender is described as black, approximately 5ft 8ins tall and driving a white BMW.
Witnesses to this incident, or anyone with information, should call Northamptonshire Police on 101.
Information can be given anonymously to Crimestoppers on 0800 555 111.