Originally Posted by
old's'cool
I haven't seen mentioned a slide hammer. Should be possible to improvise a hook through a hole drilled in side of the seatpost. For the uninitiated, a slide hammer is common fare for auto body work, among other things requiring impact in a pulling fashion.
THAT is an idea worth trying - you just need to make sure whatever hook you improvise does not easily yield.
BBM's caveat still stands though - French posts are hard to find.