Comment by fvdessen

Your pictures aren't very representative of Art Nouveau in France & Belgium. Here are other examples:

https://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/Ma...

https://www.bluffton.edu/homepages/facstaff/sullivanm/belgiu...

http://avenue-montaigne.be/wp-content/uploads/2016/04/Horta....