An alleyway in Ilkeston was cordoned off following reports of a sexual assault which turned out to be false.
A spokesman for Derbyshire Police confirmed that they received a report of an assault at 12.45am on July 27.
The alleyway close to the Morrisons development in Field Road was cordoned off with police tape for most of the day.
Police community support officers and scenes of crime officers attended the scene.
A 25-year-old woman later admitted making the allegation up.