There was a custom's border inside France from 1815[0] to 2008, with different treatment for imports/exports from Switzerland to the small part of France beyond that custom's border.
According to that article, you can still buy cars w/o EU import duties in that part of France...
[0]: Yes, as a result of Napoleon's defeat and as part of Geneva joining Switzerland.
There was a custom's border inside France from 1815[0] to 2008, with different treatment for imports/exports from Switzerland to the small part of France beyond that custom's border.
According to that article, you can still buy cars w/o EU import duties in that part of France...
[0]: Yes, as a result of Napoleon's defeat and as part of Geneva joining Switzerland.