Officers were called to Aperitif in High Street West, near Sunderland’s Empire Theatre, at 11.30pm on Sunday, May 22.
It is understood that an offender had gained access to the venue and took a quantity of cash before leaving the scene.
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Police have launched an investigation into the incident and have asked anyone with information to come forward.
A Northumbria Police spokesperson said: “At 11.30pm on May 22, officers received a report of a burglary at Aperitif on High Street West, Sunderland.
“It was reported that an offender gained access to the premises and stole a quantity of cash before making off.
"Anyone with information is asked to contact police via the ‘Tell Us Something’ page of our website quoting crime number 060254C/22.”