ducjans -I cannot speak to the rarity of this box except to say I have not seen it before. I have about a dozen of this style FN 9 mm Para boxes in my collection, but suspect that is barely a start. It certainly is NOT a common box.
I have a similar label that mentions Coppal Powder. The layout is a little different, with the main descriptive line of print reading “25 Cartouches, Cal.9 mm, Pour Pistolet G.P., et Mitraillette.” It is on four lines which I have separated with commas, although they are not on the actual label. (English:
25 Cartridges, Cal. 9 mm, for Pistol Grande Puissance, and Submachine gun"). Your label and mine are the only types I have seen that use the “Grande Puissance” initials “G.P.” in the caliber designation. (English: High Power).
My label, which is only the box top removed from the box, unfortunately, is printed for "F.N. LOT 18 d/ 53. The very bottom line is somewhat unusual for an FN box of this type - “Cde S.A.A./ N° AP, 34/53/140” I do not know the meaning of that line of print.
It is a really nice label. Thanks for sharing it with us.