I invite you to discover (or remind) Gruau. A graphic deisgner artist (truly an artist) of the beginning of the 20th century. He may remind you the work of Mucha (who is more decorative) . I my opinion, these artist are still influencing us today and have done an innovating work that is still interesting and valuable.
http://www.renegruau.com/ (this website does not shows right Gruau's Art)