A woman was sexually assaulted at the corner of Wilbury Road and Church Road in Hove.
Sussex Police said: “The 27-year-old victim was approached by a man who started talking to her between 3pm and 4pm on Wednesday (17 June) but then suddenly sexually assaulted her.
“The woman got into her car parked near by to try to escape from the man but he followed her and got into the passenger seat.
“The victim then got out of the car and went into a nearby clinic to raise the alarm.
“The man then left the scene. He is described as being of Mediterranean appearance, of average height and build and with short brown hair.
“He was wearing grey jogging trousers and a black T-shirt with a design on it. He told the woman he was 26 but appeared older.”
Detective Constable Ed Downes said: “The victim is unhurt but has been left very shaken.
“The sexual assault happened without warning in a busy area in the middle of the day which makes this extremely unusual.
“We need to speak to anyone who saw any part of the incident or who recognises the description of the man. If you saw anything at all, please contact us.”