I'm trying to identify the maker and possible era/date of this French cocktail shaker.
I'm not sure if the mark is a crab or a lobster, but it doesn't look like the French silver crab mark, which seems right because the 15G means it is silverplate not silver?
Also looks like an "S" over "A" (or vice versa). But, I can't find a match with a maker.
Given it is written in English, does that mean it was for export?
Many thanks for your help!
Full view, outside:

Bottom view:

Close up bottom view - is it a crab or a lobster? S over A or A over S?:
