Jean-Pierre Mangin believes that the two
ships included in the design of this stamp suggest that Cavelier de la
Salle reached the mouth of the Mississippi from the sea, which, as he
points out is not the case. Alvar Núñez Cabeza de Vaca discovered the
mouth of the Mississippi in 1528, while de la Salle was the first
European to descend the Mississippi River to its mouth in 1682. The
motto on the stamp says that he discovered Louisiana.
The value of the stamp 3,25fr. was "the
postage for airmail letter under 5 grams addressed to overseas
territories and certain other countries," and should have been
identified as an airmail stamp, according to Mangin.