The stamp Experts in France "Calves" created their on line
Certification system since 2015.The certificates are sent in the
PDF format as well as in paper form.In the link below information
on verification by entering the certificate number.If the certificates
ar before 2015 one must contact them for further verification.
Nevertheless some dummy sellers use these Certificates too sell
their stamp by forging the information and replacing the photo with
another fake stamp.In this case it is a 1fr Vermillon.The original stamp
was a color "Cerise" as shown in the 2nd pic.

real certificate:

The real certificate is from their safegaurded files.
http://feeds.feedburner.com/Timbres...lainJacquartIn many listings now in France we find these PDF certificates and they can be verified.