The "Navigation and Commerce" stamps were forged by Fournier and also the overprint applied on them.
Because I have genuine stamps and forging, I can give you some information to identify them:
1.Perforation. 17 teeth vertically = forgerie / 16 = genuine
2.Gumm. white, translucent = forgerie / yellow, brownish = genuine.
3.Design. Flattened fruit, fingerless hand = forgerie / round fruit, correct hand = genuine.
Some examples from my stamps:
PACKHOI overprint stamps are forgerie (17 teeth)
The pair with overprint 05 is genuine (1.5 mm between 0 and 5 is normal / distance of 2 mm is variety). Check the distances to your pair, I have the impression that it is more than 2 mm.Possible forged overprint on genuine stamp.
Guadeloupe with G&D 5 double overprint is forged stamp (17 teeth)
Guadeloupe with G&D 15 inverted overprint is forged stamp (17 teeth)