Mohammed Asif, in his 40s, collapsed following the row at Akbar's in Manchester city centre on Friday night.
Police were called to the city-centre restaurant shortly before 11 pm but he was confirmed dead in hospital.
A 37-year-old man was arrested on suspicion of assault and remains in custody for questioning. Police has started investigating with forensic officers and the area has been cordoned off for some time, the Daily Mirror reported.
Manchester city centre councillor Joan Davies, who lives next door to the restaurant said, "I spoke to him on many occasions as a neighbour, customer and councillor. He was always very gentlemanly. I was in the restaurant with friends and their little girl and he gave her a Christmas cracker."
"I think he he had been there (at Akbar's) from the start and he ran a very successful restaurant which attracts all different kinds of people," Davies said.
Exact cause of Asif's death will be announced later following a post-mortem.