A man has been arrested on suspicion of grooming offences following an incident on the canal path off Lockoford Lane in Chesterfield.
A passer-by believed they had witnessed an assault taking place at about 7.30pm on Tuesday, police said.
The area was cordoned off until about 11am yesterday while forensic examinations were carried out at the scene.
No assault had taken place.
A 35-year-old man was arrested on suspicion of grooming offences and has been released on bail pending further inquiries.