Officers were called to George Square at 3.09am on Saturday by someone saying a number of men were believed to be fighting.
A spokesperson for West Yorkshire Police said: "Officers attended and those believed to be involved had dispersed and left the area.
"No one was found with any injuries."
George Square was taped off on Saturday morning while police investigated.
Anyone with information should call police on 101.
Information can also be passed on anonymously via Crimestoppers on 0800 555111.