The victim’s wife said the tourists were driving a Porsche Panamera when they signalled her husband to stop before exiting the car and and beating him without explanation.
Police identified the suspects as Vincent Raymond Bugeya, 34, and Julien Gerard Rene Vincent, 28.
They were arrested by police from Borphut Station at a bar not far from the spot where they allegedly attacked Somkhuan Songkot, 43.
The pair were detained at the police station pending a hearing at Samui Court to bring formal charges.
Somkhuan’s wife, 47-year-old Lakkhana Salao, told police the assault took place at 9pm while her husband was taking her home by bike after work.
Lakkhana said Somkhuan overtook the Porsche at Phru Chawaeng Intersection but the driver sounded the horn and drove after them. The driver then signalled the couple to stop in front of Wassana shabu shop.
Lakkhana said she and her husband thought the tourists wanted directions, so they stopped. However, the Frenchmen exited the car shouting at the couple.
Lakkhana said the passenger threw a punch, felling Somkhuan, who then tried to escape into the shabu shop. She said the Frenchman followed him, still throwing punches until Somkhuan fell to the pavement, hit his head and was knocked unconscious.
Lakkhana said the incident was recorded by a customer in the shop who later shared the clip with her.
Shop customers also called an ambulance and the police.
Lakkhana said doctors treating her husband had diagnosed a brain haemorrhage and ordered surgery to drain the blood.
Pol Col Yutthana Sirisombat, chief of Borphut police station, said the two suspects had arrived from Hua Hin to tour Koh Samui. Police will seek permission from Samui Court on Tuesday to detain them pending further investigation before they are formally charged in court, he added.