Gueye, 31, of Sheffield, is a registered sex offender who has failed to meet the requirements for registration.
Gueye is described as black, slim, and about 6 feet tall. His hair is black.
Police want to hear from anyone who has recently seen or spoken with Gueye, or who knows where he may be staying.
He is known to frequent the Brighton area of Sussex and is thought to be in the Brighton or Sheffield areas.
If you see Gueye, do not approach him and instead dial 911. Please call 101 if you have any additional information about his whereabouts.
You can also contact Crimestoppers anonymously at 0800 555 111.