Burglars broke through two brick walls to gain entry to a city centre jewellers.
The break-in happened at Trinity Goldsmiths in Forman Street overnight between Wednesday and Thursday, December 5.
The suspects gained entry to the property before removing brickwork from internal walls, creating a hole to crawl through into the jewellers.
A neighbouring property was also damaged and had bricks removed but it is believed nothing was stolen.
The offenders fled empty-handed after a smoke cloak device activated inside the jewellers.
Police detectives are now appealing for witnesses and information.
Detective Inspector Ed Cook, of Nottinghamshire Police, said: "A team of detectives is now working hard on this investigation and we are pursuing a number of lines of enquiry.
"We're appealing to anyone who saw any suspicious activity in the area overnight or who has any other information which could help us with our enquiries to get in touch with us.
"If you have any information, no matter how small or insignificant it may seem, please call Nottinghamshire Police on 101, quoting incident number 7 of 5 December 2019, or Crimestoppers anonymously on 0800 555 111."
