The attack happened in Donegall Square North area and police suspect the assailant may also have used a Taser weapon on his hapless victim.
Detective Sergeant Eric Fairfield said: “We received a report shortly before 7pm that a man, aged in his sixties, had been assaulted in the vicinity of Belfast City Hall by an unknown male.
“It was reported the suspect pinned the man to the ground before punching him and then fleeing on foot.
“It was also reported what was described as a Taser stun gun may have been used by the suspect during the assault.
“This must have been an extremely distressing ordeal for the victim who was treated at the scene by staff from the Northern Ireland Ambulance Service.
“The suspect is described as being of a heavy build, with black hair and thought to be aged in his late twenties.
“He is reported to have worn a red Adidas tracksuit top that was zipped with a white hood underneath, black tracksuit bottoms with white stripes down the side and white trainers.
“Our enquiries are at an early stage, and I would appeal to anyone who saw what happened to get in touch with us.
“I also want to make an appeal for witnesses and information following the report of a robbery at commercial premises on North Queen Street in Belfast which was reported to us at 00:30am this morning.
“It was reported that two males entered the premises; one of whom was armed with what was described as a Taser stun gun.
“They threatened a member of staff before fleeing with a sum of money.
“The staff member was physically uninjured, but has been left shocked by what must have been a traumatic ordeal.
“One of the suspects is described as being tall and wore a red and white Adidas jacket, green shorts, white trainers and had his head and face covered.
“The second suspect is described as wearing a blue/green-coloured jacket with white stripes on the sleeves, grey knee-length shorts and had his face covered.
“We believe these two incidents may be linked and I want to appeal to anyone who has information about either of them and which may assist our investigation, or who witnessed either incident to call detectives at Musgrave on the non emergency number 101, quoting reference number 38 of 28/04/19 or 1044 of 27/04/19.”
Alternatively call Crimestoppers charity on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.