Help to identify umbrella gun / pepperbox?

[argusdes]

I recently inherited an umbrella gun with a stag handle, 4 side fluted dagger. The markings on the side say "Marque de Fabrique" "P.T" & "Brevete S.G.D.G."
It has a collapsable trigger & hammer which slides into a brass tube at the end of the umbrella shaft. It is a six shot revolver (I am assuming a rimfire). There is also a decorated brass ferrule at the base of the stag handle with a push button release (release it from the brass tube). The only other marking is at the end of the revolver - a stamped "6".

The only thing I know about this is that my grandfather may have brought this back after WWII.

If anyone can give me information of the background, manufacturer, or origin I would appreciate it.

 

[Gordon]

You should try in the Harvey Nolden forum below. However I doubt it can be identified as other than a small custom french maker. You have to measure the bore, it may be a pinfire or? I would presume it is old enough and weird enough to not be a BATFE theat, like I say measure and a picture would be most helpful.