Is it your 911- or you just bought it? If it is yours there is no tax in France if not there is a lot of logistics and paper work involved.Also it is good to know some peeps in France to help you.When i imported my 911 from California-living there in 2009...no tax for me drove on my CA plates for 1/2 year there after i got it changed to French plates...I do not think anybody ever checked for matching numbers on mine...Just, i had too big rims-8th and 9th, but the Porsche boss in Paris dealer helped me..saying i was legal with those....other that this all good.But my 911-is euro model...was looking for it for 4 years in CA back in 1990`s....got it in 1996...
To be honest..if you are not attached to your 911 ,sell it -you can always get one here in Europe..less hassle with the registration
Ivan