The case occurred in Lyon.
The patient, who died earlier this month, was severely immunosuppressed, meaning their immune system was badly weakened.
The French government said neurological complications before the death were most likely related to the infection, and that preliminary evidence points to an insect bite as the source.
Authorities are still investigating how the infection happened.
Still, several European countries are on alert, since the region was considered free of the virus until a few months ago.
This summer a variant called Shamonda-Europe was detected in livestock in Switzerland, followed by cases in Germany, France, Austria, Belgium, the Netherlands, Liechtenstein, Italy and Spain.
Ben Brennan, a virologist at the University of Glasgow, called the finding scientifically important but said it is not yet known whether the virus contributed to the death.
David Roiz, a scientist at Spain's Institute for Game and Wildlife Research, said it is premature to draw conclusions and urged vigilance rather than concern.
The virus was first identified in Nigeria in the mid-1960s, with sporadic livestock infections reported across Africa and in Japan. Biting midges, tiny gnats, are the main way it spreads between animals. Cattle are the main host because they show visible symptoms, including fever, diarrhea and reduced milk production; infection in pregnant cows can cause miscarriages or severe calf deformities. Sheep and goats can be infected but show no obvious signs. No vaccine exists, so control relies on insecticides and repellents. Spain's agriculture ministry says two genetically distinct forms, Type 1 and Type 2, are circulating in Europe, and that both were confirmed on farms in 37 French provinces in early September.