edi_local
This likely unique to Swiss registered cars driven to neighbouring EU countries. It wouldn't apply between FR and BE, or between DE and NL, etc. All EU countries and freedom of movement of goods and services would preclude that. And it isn't for cars taken outside of the country of rental for a few hours, or even a few days. It's for cars rented in CH that spend less than an hour total in CH and used primarily in the neighbouring country.
For years the French just ignored it. But they need taxes now, and are looking for every centime they can get.
As I noted you likely can get a cheaper car from the French side (and still be on the motorway in less than 5 minutes).