Hi all,
I bought this today from a lovely retired couple in their 90's who had discovered it along with two others in a French farmhouse restoration they did in the early 1940's. When they retired back to the UK they brought this one back with them as it was in the best condition as the other two were damaged. They were convinced it was pre 1940's.
I've seen very similar Seguso Murano designs but this does appear to be a older due to its Iron work (note raised joins/brackets) and the glass is blue (I haven't seen any similar pendant bubble caged lamps/lights in this colour).
There is no label or signature that I can find.