Hi All,

I have recently started collecting the first issue of French stamps (1849-1850 Ceres). Fully aware that this
area is a minefield in so far as forgeries are concerned, I got hold of the Serrane & Brun guides to fakes and
forgeries to hopefully enable me to identify any problem stamps. However I have quickly realized that this is
far from an easy task.

I bought the attached stamp as a Sperati forgery, but upon submission to Mons Brun, it turned out that while it
is indeed forged, it is NOT a Sperati forgery. So one must also be wary of forgeries posing as the products of
other forgers!

What are the tell-tale signs of this forgery that I should have spotted?
   
Thanks in advance to whoever may offer much needed guidance.

Regards
Ray