Anne thank you for the additional information
Do we know which other makers made this shape please?
The decor may not be a way to decide who made the vase. Could it be possible that different enamellers painted in different ways on say for example, Legras glass vases? Could it perhaps be possible that techniques may change depending on decorator/period maybe?
I understand what you mean about the gilding on the rim. Would that be a definitive no to it being from Legras then?
Legras made a lot of glass. Maybe it wasn't decorated in France?
Likewise in Bohemian glass, there are many examples of Harrach making the glass but the decoration being done elsewhere.
Also examples of other Bohemian makers making the glass but the decoration having been carried out by another finishing house (i.e. not by the glassmaker - Loetz is one example)
I wonder how the base is finished?
Sorry to quote such a large post but several things are mentioned.
Personally, and this is just me, i think that a decor often is a signature in itself. If the shape's familiar but the quality or usual style is not there, then it might make one wonder what's going on. Of course shapes and styles do look familiar and we can all recognise a shape or tell if a piece, shapewise, has been meddled with somehow, but on the other hand, we've never seen everything that's out there...i guess it's a topic that can be discussed endlessly. I can't tell you of this shape is used elsewhere, it probably is as it isn't a very complicated one but i couldn't give any examples right now.
Re the french outsourcing something … I wonder if anything would have been considered good enough, and I don't mean this in a nasty way, but the french are just … well, very french, lets keep it at that. I would need to do some reading to see if anything's mentioned, but there were so many decorators in France that bought blancs at their usual adresses, Legras being a supplier too, and I wonder if there would have been a need to go abroad, but you would expect to find at least a signature if it was from an individual decorator.
Going through some books I find that the enamel on this vase is so thin, it almost looks painted and looks similar to some of the decors found in Germany, done by different houses, but i'm going into, still, unfamiliar territory now ...