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.