An 81-year-old man was diagnosed with meningoencephalitis after he returned to France from a Pacific island cruise in January.
French researchers said they found Zika in his spinal fluid, which gives cause to suspect that his illness could be related to the virus.
Earlier this week, different researchers linked the Zika virus with myelitis, an inflammation of the spinal cord, which causes paralysis.
It has spread quickly throughout Latin America and world health officials are looking at ways to stop the mosquitos that transmit it.
In the French Pacific island of New Caledonia, which last year saw an outbreak of mosquito-borne dengue fever, a start-up has come up with a system of shredding old tyres to put in drainage ditches.
"The system keeps the female away from stagnant water and prevents it from laying eggs on the surface or nearby," explains entomologist Françoise Mathieu-Daudé. "So it prevents larvae from developing in stagnant water.
"It does allow drainage, though, even when there is heavy rain, as we often have here in the tropics. The second advantage is that the system uses recycled tyres, which is interesting, because tyres can be real reservoirs for the vector insects."
Other methods of trying to tackle Zika-carrying mosquitos include releasing genetically modified mosquitos or large numbers of sterilised males, or even infecting mosquitos with a bacteria that prevents their eggs from hatching.
The World Health Organisation is meeting next week to determine which methods would work best.