... the weight which contains a spiral of bubbles, weighs nearly 1.5Kg and is 10cm diameter. Big
That's probably why, in the literature I have seen [which is not much] about those 1960s Schneider pieces, they have been called "Glass Globes" rather than "paperweights".
And my understanding is that the signatures on the 1960s "globes" always included "France" as well as "Schneider".
This whole topic of false Schneider signatures on paperweights was discussed, with no proper conclusion, in a Yahoo!-based paperweight forum some years ago (I am no longer a member of that forum, so can't easily extract any info). But I do recall that somebody pointed to the signatures in Anne Geffken Pullin's Glass Signatures, Tradenames and Trade Marks
and suggested that an example they had on a weight matched one as shown in that book. I pointed out that when compared to the marks shown in Edith Mannoni's book, Schneider
, it was clear that the Pullin versions had lost part of the relevant detail in the print process! (Also, the form of the "amphora" section of the mark referred to appeared to differ with respect to the handles.) I mention this here, just in case anyone does start browsing the Pullin book in this context.