The stamps were produced by applying a typographic overprint to an earlier regular
issue stamp, as a special offering in connection with an aeronautics exhibition.
A substantial difference in value exists between the regular issue stamp and the air post
overprinted stamp thus leading to many fake attemps.
Some of these are described along with the features of the genuine.
Sound Advice - only get them if certified as I have seen good fakes in prestigious auctions without certificates or only "signed".
The Genuine
Features of genuine and forged overprints.
1. The genuine overprint measures 12mm from wingtip to wingtip. In some forgeries it is between 12.5 and 13mm.
2. The accent over the letter “e” generally does not touch the letter. Not true in all cases
3. In the genuine, the forward wheels have a distinct oval shape; forgeries are often circular.
4. The dot over the "i" should be square, not round.
5. Another clue is that the lettering is not all on the same line.
6. A rounding-off of the tail rudder also is suspicious.
7. Original overprints have 8 vertical lines of shading on the fuselage; some forged examples have 7 or fewer vertical lines.
8. The tail wheel should be aligned over the "t" of "Poste" or between the "t" and "e" of "Poste". Forgeries generally place the wheel directly above the "e", or to the left of the "t".
9.The capital P and A should measure 2.5mm high. In some forgeries they are 3mm
Comparison of a Certified copy (top) and an eBay "signed" copy
In the Fake...
Crossbar in A is inclinedAccent over e is not like genuine
Wheels appear to be round
Large dot over the i
Openings in the e's are smaller
Below the common "Kull" fake
Note the rear wheel position, round front wheels and the dot placed too high
More Fakes
The P is leaning left
The t is rounded
The A crossbar is too low
Overall very smudged effect
References
-Airmail Stamps: Fakes and Forgeries, Newall, Alexander F. 1990.
-Fakes and Forgeries of the 20th Century Dr. R G. Gethin, pub. 2006
-Genuine and Forged Overprints of France’s 1927 Air Post Issue, Christopher J. Palermo 2019
-Various stamp forums
