On first sight you might think it impossible to insure a British registered car in France. But there are ways to let you drive the car fully insured, still using the British registration, for a stay or even permanently.
You Must Have Insurance
You must have at least third party insurance to drive a car in France, just like anywhere else. It is a legal requirement and driving without insurance can become very expensive if you get involved in an accident.
Driving to France
Tourists and visitors can take a British-registered car to France for vacations and short stays without any problem. Under European regulations, the British insurance cover extends to France during this period. How long the deadline lasts is very vague, because the authorities do not actually know when the vehicle actually crossed the border.
Keeping the car in France
Under French law, if the owner of the car is resident in France, he must re-register his vehicle with French license plates after a grace period of three months. Again, the authorities do not actually know when the vehicle entered the country, but the police could well notice if a foreign vehicle stays for a long time in one neighbourhood.
French companies will insure the car only for a few days, long enough to attempt the formalities to change the registration.
If the owner of the car does not live in France, there is no need to re-register it with French license plates. So you can have the car registered as being owned by a friend or family member, or even a company, in the UK, who take out British insurance and then "loan" the vehicle to you. Of course your name must be on the insurance policy as an additional driver.