France's 50-franc airmail from 1936, C15, has a variety -- C15a. Scott says the burelÃ© is reversed. But there are no pictures of the reversed burelÃ©. So how do you know which is which?
Below are the two stamps, with drawings from the 1982 Yvert:
France C15 normal burelÃ©. Leans to left.
France C15a reversed burelÃ©. Leans to right.
I just acquired the copy of Scott C15. Although it catalogs for less than C15a, it is much harder to find. Most copies I have seen in auctions are actually C15a.
This came from a Kelleher auction in the United States. That auction had SEVEN of these things, all described as C15. But five were actually C15a's.