On the other hand, sparkling wine from California ''is'' called champagne. Trademarks, especially in the international arena, are seldom absolute.
In any case, that was real nice to give a "french" name to the server and we appreciated the choice.
This said, trademark or no trademark, the french Champagne is best.
And why not renaming larousse to champagne ? It seems there is a consensus. It is not in the name that lays the value but in the «bottle». :)