Police today said that they were seeking witnesses to the assault, which happened in the South Yorkshire town some time between 12.45am and 1.30am on Saturday.
The man and the woman, aged 30 and 32, were walking along Cemetery Road when they were approached by the group of five men and two women.Members of the group, who are all thought to be in their late teens to early 20s, then assaulted the couple with items including a piece of wood and a length of plastic.
Both victims suffered minor injuries which needed hospital treatment.
One of the men involved is described as wearing grey tracksuit bottoms and had his top open, showing his chest.
A women with the group is said to have been wearing heavy make-up and had blonde hair.
Officers are working with the victims to obtain further descriptions of those involved and are asking anyone with information to come forward.
Call 101, quoting incident number 119 of 27 May 2017, or Crimestoppers anonymously on 0800 555 111.