France 1937 Nansen Stamp Or Proof? Paper Question.

Good morning all. On transferring a few recent purchases to my France collection, I came across this, the only unused item in the lot. It is the 1937 "Nansen" 50c + 25c stamp, which is in great condition but appears to be backed with card or thick paper. The perforations (P13) are correct, could this be some sort of proof? My Maury catalogue mentions a special printing "sur bristol" but I cannot find out what "bristol" refers to in this context. As you see from the photos, the last 2mm of the stamp at the bottom edge are free of the backing.
Any assistance gratefully received.
Regards
DavidR

David - Are you sure that the double-thickness isn't created by the stamp-edging having been folded behind the stamp, then stuck? It looks like that from the base of the stamp.

Bristol paper is thick card like paper

Geoff wins for the Twinkie!

Hiw do I claim my prize, please?

Hi Geoff,don't know if I am derailing your Twinkie here. The bottom right corner of the backing allowed the tweezer in, see photo. Wouldn't the stamp edging you mention be the same colour as the stamp? Gum appears to be more brownish than the backing.
Regards
DavidR

Because the front of the stamp would have been exposed, the hidden selvedge could have retained more of the original white.

Perf12, would the printed on bristol be perforated as per mine? Or have a space all round the stamp?

You could be right Geoff. Not sure if this is too stiff to just be doubled-over selvedge though. Will make a note next to it reading simply 'paper?'

Thanks for your help gents.
Regards
DavidR

Thank you for the opportunity to win a Twinkle, which Rog is posting in Topeka as we speak.

It is not too late to substitute a Ring Ding. Let me know.

It looks to me like I can see paper threads where the perfs have been pulled apart on all four sides, so that wouldn't point to folded over on one side. Maybe two sheets were stuck together and then separated? Tough to tell with the blurry images...

That second picture makes it clear what the coloured line at the bottom was. The first looks like a flash was used. I also think it confirms what GeoffHa suggested: a stamp with the top selvedge that has been folded back and got stuck. If the fold is sharp enough, the paper could break across the perforations and show fibres even at the top.

Looks like a two stamps stuck together. The two stamps were perforated seperately. Soak in water to find out ....

Sticking with Geoff. The selvedge is the exact right height for this and the perfs match at the top flawlessly which to me says folded over upon itself.

SO, the Twinkie HAS been posted. Bon appetite!