A shop manager who was opening up for the day was threatened by a man who pushed an object into her back before stealing money and jewellery.
Police are now appealing for witnesses to the robbery at the Cheque Centre in Foundry Walk, Daventry.
As the manager of the shop was opening up, she was approached by a man. He pushed an object into her back, told her to go into the shop and demanded that she open the safe.
He stole cash and jewellery, which he put in a rucksack, and then left through the fire exit at the back of the shop.
The offender was about 5ft 5in, with a slim build and spoke with a French accent. He was wearing a black long-sleeved top and a black full-face covering. He was carrying a navy blue rucksack, which had some kind of logo printed on it.
Witnesses or anyone with information are asked to contact Northamptonshire Police on 101. Officers would particularly like to talk to a man who was seen walking past the shop, possibly carrying a cup of coffee, at about the time of the robbery.
The robbery happened on Tuesday April 22 at about 8.30am.
Alternatively information can be given anonymously to Crimestoppers on 0800 555 111.