It happened near the Theakston bar, near to Gate 10, between 11.50am and 4.45pm on Saturday, 24 August.
A woman who was standing in a queue was touched inappropriately.
The suspect, who appeared to be attending alone, is described as being in his late 20s to 40s, broad built and was wearing a flat cap and jacket. His appearance is described as not smart, which made him stand out.
Please email olivia.kingston2@northyorkshire.police.uk if you have any information that could help our investigation.
Alternatively, you can call North Yorkshire Police on 101, select option 2 and ask for PC 711 Kingston, or contact Crimestoppers anonymously on 0800 555 111 or via their website.
Please quote reference 12240157046.
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