my opinion Ken is that this is neither a deco colour nor a deco shape. My literature on these things is rather meagre and about the only reference source I have is the proverbial 'MADE IN CZECHOSLOVAKIA' booklet by Ruth A. Rorsythe.
This illustrates dozens of scents/perfumes from Czechoslovakia from the 1918 - 1938 period - the height of the origins of deco style - mostly examples with stoppers and a few atomisers.
In the book, the non-atomisers are typical of deco designs, with very OTT stoppers, and most are in non-frosted finish, with both clear and a variety of colours, but it seems nothing like your blue, which I'm assuming is a sort of watery turquoise.
The outline shape of your piece, in my opinion, shows curves rather than an angular shape which was one of the features of deco design - the flat polished base would probably be the only feature it has in common with Continental deco style glass.
None of which means yours doesn't hail from Eastern Europe, but I don't think it comes from the inter war years - then again it may come from almost anywhere.
I've attached a picture of what are possible some deco period scents - and my opinion is helped by the metalwork which does look to have deco styling, even if the glass doesn't.
Sorry this is unhelpful.