Lee Elton Fisher, a Territorial army soldier who had served in Iraq, had been working as a stand builder at the Tax Free World Exhibition, which is taking place in Cannes this week.
According to local newspaper Nice Matin, trouble started at around 3am when an argument broke out between Fisher and his friends and a group of local men.
PA reported that Fisher had been enraged at the cost of drinks in a lap-dancing club. He then stormed outside to confront a man handing out promotional fliers and a fight broke out.
"People came over to help the man and Mr Fisher found himself facing several individuals," said a police source. "His own friends came over but two of them were also attacked. One was punched in the nose and the other on the mouth. They were chased off."
"After that, the situation appeared to calm down but suddenly Mr Fisher was punched in the face. He fell to the ground, unconscious."
The dead man was married and came from Camberley in Surrey. An autopsy is planned for Thursday to establish the precise cause of death.
Three French men, aged between 25 and 30, are being held by police.