North Yorkshire Police says the sexual assault by touching happened in Popworld, in George Hudson Street, in York city centre, between 1.30am and 2.15am on Sunday, December 1.
A police spokesperson said: “We are appealing for witnesses and information about an incident of sexual assault by touching that occurred earlier this month.
“We want to hear from anyone who has any information that could assist the ongoing investigation.”
If you can help, please email lyn.knight@northyorkshire.police.uk, or call North Yorkshire Police on 101, quoting reference number 12240219142.
