I hope you can see the image. The mark is S. S.
Guillaumot Paul-François, 40 galerie Montpensier, Paris, active from 1907
or
Gigon Paul, 38 rue des Gravilliers, Paris, active from 1912
Is this a symbol of a knight’s head with a helmet?
I don’t see even a hint of a “PG” in that mark anywhere. Do you? And what would “SS” have to do with it?
These are just my speculations based on scant information and illegible photographs.