The signature on the weight compares quite well, but has some clear differences, with one of the many real versions used from 1918 to 1939 as shown in Edith Mannoni's book, Schneider.
Certainly, the form of the weight, which I suppose could be called a "double-ended Marbrie" (??) does not match with what is known of the Glass Globes produced post-war by the Schneider brothers, and pre-war Schneider did not make paperweights. So the conclusion on that evidence alone is that the signature on this item has to be false.
I agree that the weight is well made. I actually acted as servitor (with extremely little prior experience!!) in a fairly recent demonstration of making a Marbrie weight. It was surprising how many separate processes were required and how hard it can be to maintain an even flow of the pull-ups and also get everything centralised in readiness for capping with a cane. The fact that the weight shown here has a separate Marbrie-type pull at both the upper and lower sections (and there are opposing-direction pulls, too!) indicates it was made by somebody with a lot of experience of the work required. Sadly, the upper pulls don't all quite make it to the top of the weight, so it does show a degree of "lesser" expertise.
Personally, I do not think the maker of this weight would have been involved in a false signature, if only because of the idea that somebody with the necessary skill to make the weight would quite likely know that such items were not products of Schneider. I reckon it comes down, as is so often the case, to a dodgy dealer or export / import network having the signature added later.
That it has two distinct Marbrie loop sections (or perhaps Marbrie top with pull-up lower body) should, in theory, make it easier to narrow down the maker. But I have no idea who that may have been!