However, Hazra denied the allegations and accused the man of "infringing" on his privacy in a sozzled state.
According to Suresh Roy, a resident of Kasba in South Kolkata, the incident happened in the pub of a hotel on Ho Chi Minh Sarani under Shakespeare Sarani police station at around 10.30 p.m. on Saturday.
Roy in his complaint said he had gone to the pub where Hazra, a former Trinamool Congress MP, was sitting just opposite him.
"One of my friends said he was a politician. So I took his photo. But Hazra rushed towards me and starting beating me. When I protested, he threatened me with encounter as he had Y class security.
"I was pushed out of the hotel, my gold chain was snatched. My mobile has been damaged," Roy alleged.
Roy claimed he had to go to the SSKM Hospital for a brain scan as his head was reeling.
"But when I went back to the hotel with the police, he had already fled," he said.
Hazra, on the other hand, claimed that he had gone to the pub with some friends to celebrate the birthday of one of them.
"There a man, completely sozzled, requested me for a selfie. Despite my security guards' objections, I allowed him, as he said though he was Trinamool worker, he was a big fan of mine," he said.
"But then my security caught him red handed while he was capturing my video from various angles and WhatsApping them to somebody. When my security stopped him, this completely drunk man abused them," he said.
Hazra claimed then his security drove him out of the place.
Calling the incident an infringement on his privacy, Hazra said: "Nobody should do anything which creates an uneasy situation for somebody. Legal action will be taken against him. I am sure when he went to lodge the complaint he was not in his senses."
( With inputs from IANS )