I do not know much French so I think that is what it means. The number 1 and lots of airplane markings so I assumed.
Folded in four but since this is airmail paper and very thin it did not seem to affect the whole as much as you would think. Opened cleanly along the top edge.

Posted on Tuesday, August 31, 1948:


Transit stamp Friday, September 3, 1948:

Reception stamp Saturday, September 4, 1948.
