I'm not sure about the other EU countries, but in France at least, the law actually requires a dealership (and any other seller) to sell a vehicle/product/servi

I'm not sure about the other EU countries, but in France at least, the law actually requires a dealership (and any other seller) to sell a vehicle/product/service to any private customer. You either sell your product to anyone or you don't sell it at all, except in rare cases where the law specifically prohibits it e.g. alcohol to minors or, like in the case above, where the customer acts in bad faith.