This is where backstories are supposed to come into play. There are stacks of requirements for theme parks that limit and dictate a variety of aspects of any design, from the legal to the practical. Some of these requirements can be very prescriptive but few are absolute.
Ops almost certainly does have signage requirements that dictate things like visibility, prominence, size of text, amount of illumination on the face of the sign and other criteria. What they probably don’t dictate is the actual style of any of those elements besides legibility, meaning an overly ornamented calligraphy is probably going to get rejected. Even just switching to a blade sign would evoke a more old urban feel that would actually be more visible to guests. This is what backstories are supposed to help inform. How would a small crêperie expand to the size of a Disney theme park facility? How would a sign that meets Ops’ requirements be designed and added?
One of the really bad things about this expansion, Riviera and the Skyliner is the way that they reduce Art Nouveau to a mere ornamental appliqué. Outside of the intricate Ratatouille marquee arch it is largely some frilly lines that are painted on a bare surface and “Voila! It’s French!” They’re not just on this sign, but also the bare walls of the ugly yellow building. The Skyliner building tries to add some ornament but it is incredibly poorly realized with tube steel and metal strips. Art Nouveau was an entire style of arts and crafts, not just painting and other visual arts, but furniture, interior design, architecture and even structural design. It was an all encompassing design movement. Instead of some painted lines on the crêperie sign why not do a full on Art Nouveau sign?