Do we pay more for highway tolls?

No, because the Faraday is less than 2 meters tall.

Pour information, sur l'autoroute, la remorque peut changer la "classe" de votre véhicule et donc augmenter le prix du trajet.

It depends on the overall height of the vehicle (excluding any cargo such as bicycles or roof racks):

‍

Most standard luggage trailers are less than 2 meters high and therefore don’t cost a penny more at the toll booth.

On the other hand, a large trailer or a tall boat trailer will put you in Class 2.