i've had Uk reg cars over in france for a long time now, with never a problem
but to register a uk car in france
step 1, you'll need to get a certificate of conformity for it ( an original from the manufacturer a copy won't be acceptable)...... sometimes quite hard for rhd as the UK never issuse this document with new cars,
this will have all the relevant infor and mainly the fiscal horsepower figure and the type approval code,
if you don't have these 2 valuable pieces of info it's nigh on impossible to register the vehicle in france the prefecture will just tell you to come back when you have the info.
once you have the COC take the papers for the car V5 etc to the local tax office (Impot) and fill out the paperwork explaining there is VAT or import tax due on the car to prove this you must give mileage and first registration date, car must be over 3 years old and have done more than 6000 kms then no tax is due.
take the car to Controle technique ( MOT) plus you'll need to change the headlights over for Lhd versions and set them up or it will fail before you go,
once you have an MOT report pass or fail take all the paperwork you've got, MOT, V5 Tax docs COC (you don't need insurance docs at this time) to the local prefecture and hope they will process your application, you pay a fee to register it according to the fiscal horspower figure, bigger the figure the more it costs, once you've done this, they will tell you your number plate details and you can go and get a set made and stick them on the car.
can you see why i keep my cars uk registered......no one really cares, they don't have road tax here so no need for the government to keep hassling you to register the car
for insurance, you need to pick and choose for euro cover we use a good company in the uk so no problems how many times or how long the car is in the euro zone for us.
the best thing to do.... keep it on uk plates bring it back to the uk once a year for MOT run the car into the ground and when you need to scrap it just break it and sell it for parts on ebay as parts fetch good money over here unlike in ther uk, buy a replacement in france VOILA.
good luck Lee
any more info give me a bell any time before 1930 UK time