A woman was assaulted in Shelley Road, Wellingborough, between 7pm and 8.30pm on Saturday, February 7.
A spokesman for Northamptonshire Police said: “It is believed the victim and offender were sitting in a blue Renault Clio, and that the offender then assaulted her by kicking and punching her, causing a cut on the side of her face.
“He then punched the car windscreen, causing it to crack.”
The offender is described as being about 24-years-old, 6ft 4in tall with a skinny build and short dark hair swept to the side. He was clean-shaven and wearing white trousers, blue jeans and a black jumper under a black jacket.
Officers would like to speak to any passers-by who witnessed the incident.
Anyone with information should phone Northamptonshire Police on 101.
Alternatively, phone Crimestoppers anonymously on 0800 555111.