And if yes, could they cross the border into Spain and return?
I also saw the same question on FB today but I suspect that was your friend. I don’t know the answer BTW.
Have they checked with their Swiss car insurance company that their daughter would be covered to drive the car like that?
But I am not sure if that is the case if non EU. A separate question. And not sure if not in CH either?
One thing I always do, however, is prepare a letter in English/French/(other relevant language if applicable) that I, (Bossa Nova, place of residence, date of birth, phone number) permit family member (Name + date of birth) to drive my car with registration number VD XXX XXX for the period (dates). In case they ever get stopped by police or questioned at the border, they can provide this document justifying their use of my car. Have never had any problems using this approach.
I believe this would only be an issue if the US driver was also a CH resident.
How long is the US driver visiting for? If it's under whatever time France requires to change licenses (I don't know what those limitations are in France; in Switzerland it is 1 year), it should be no problem for the US driver to drive around with only US license (just as they would if renting a car).
They should make sure that the car is fully insured (and double-check with insurance that it is indeed insured for a "third country" driver -- there is weird fine print sometimes that is surprising) and that there's ample insurance for liability and medical accidents (US health insurance doesn't apply in Europe, and you just want to make sure there aren't any surprises just in case). They should insure at the highest level required out of whichever countries they're planning to drive through (Spain may have slightly different requirements than France, for example. I would wager Swiss insurance has highest minimums of coverage, but again just doing due diligence there).
There are no problems with a person holding a US driver's license to rent a car in Switzerland and drive through France and Spain. Thus, as long as the person is legally allowed to drive the car (what would you need to show to police to verify this?) and they and the vehicle are properly insured, there should be no problem. If this is a temporary trip, there is no worry of customs/VAT, because it's just for tourism purposes, and this isn't taxed, aside from things like the Swiss highway sticker and the like.
If they're taking the car to Spain to then live and register there, it opens a somewhat different can of worms, but from my understanding, this isn't what you're asking. (Please correct if wrong.)
So what’s different from her joining her family in France?
Provided she is covered by the insurance I see no issue.
Important is the place of residence. This shouldn't be in the EU. Non EU citizenship and non EU driving license can be evidence that this might be fulfilled.
If they are US residents and tourists, they can bring your car as tourists into the EU custom region, based on the rights given by the Treaty of Istanbul on temporary admission. You should provide them with a statement, that they can us your car abroad.
Here a template with many languages from Zurich insurances:
https://www.zurich.ch/-/media/zurich...ttpersonen.pdf
You might sign it in front of a notary to make it more official (costs CHF 20).
and might even affix an apostille (costs another CHF 20).
Article 215 Commission Delegated Regulation (EU) 2015/2446
Tom