The biggest problem I have in replacing axles is that you need the cone
and the threading to match. I don't recall, but I believe Shimano and Maillard
axles have different threading (someone will correct me if I am wrong).
This is a problem because you can't put your existing cones on the Shimano
axle and the Shimano axles probably have a different diameter then the Maillard.
As I said, I don't recall the details - but you have to have them right or you
are not going to get what you need.

And it is possible I have some french threaded axles, I might have an opprotunity to check when I get home tonight.