Is there some context to this, because I refuse to believe whoever designed (and produced) that didn't know the difference between those words/phrases? Do they just hate the French?
The sign looks like is assembled from 3 parts, the middle part is most likely from the "goodbye" batch and got mixed up (either through error or some troll) with the welcoming sign.
Do I dismiss the possibility that the fact that the french part is interchangeable is intentional? No :> German-speaking people (regardless if they are from CH, AT, DE, or LU, love to troll/bash the French
and the English
and the Austrians
and the Swiss
and the Germans