The 60-year-old, who has not been named, was among a group of staff from trust company Dominion who were struck by the vehicle shortly after they left a restaurant in Rennes in the early hours of 1 August.
He was left fighting for his life with multiple internal injuries after being trapped underneath the car which had flipped onto its roof. He was left in a coma in Rennes General Hospital and was later transferred to the General Hospital. He died on Wednesday.
Five other Islanders were also injured in the crash. A 31-year-old woman was seriously injured and was treated in Rennes General Hospital but has since been discharged. Two other women, aged 21 and 27, and two men, aged 18 and 45, suffered less serious injuries and have since made a full recovery.
The 35-year-old French driver was arrested at the scene and later charged with drink driving. An examining Magistrate is now leading the investigation into the death.