it is possible ...I know a french guy with a winnebago brave 29ft
but it is difficult as others have suggested !
the main reason why few do it in france is that almost no-one has a licence to drive a vehicle over 3.5 tonnes presuming the vehicle meets EU normes
re-wiring indicators and change to 220v equally applies in germany
getting type approval documents without a french importer is difficult but such documents will be accepted from the manufacturer if presented in the correct form ; normally lpg conversions done elsewhere are accepted , but once registered the vehicle can only be converted by an approved french professional
presumably you speak french so why not seek counsel from one of the french websites ?
but registering in the uk first would NOT be a good idea ...you would achieve nothing
and someone in belgium would probably know the wrinkles about importing into france
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