Let's put it this way: you will never be able to find a good copy of this poster. I own 3 of them, and they are all the same. The paper it was printed on is horrible. So if you like it and want to put it up, $200 for linenbacking seems good to me. It is a pretty rare and iconic poster by Guy Gérard Noël. As far as worth, I don't know, I don't keep track of these things, but if
Besson sells it for 700 euros, it is a least worth half of that.
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