I live in Italy and I can say thet "for some strange reasons" Coffers don't go on sale becouse they say that they are "continuous" models. I don't know if the same policy applies to the Miu Miu brand shop in Milan.
Second: normally shops reserve a 15% discout anytime during the year to their devoted customers. This happens to me in my local Prada shop, but if I go elsewhere I'm not known they propose me full price. This happens to my girlfriends too in other main italian cities.
Devoted customers are on a "mailing list" so thet we can access to sale prices in the week immediately before official sale. This means that aficionados often assault dicounted bags before others... I got a 40% discount on a Marc Jacobs 2 weeks before 6th january (date for official winter sale).
This is a kind of consideration treatment to best customers....some might call it "italian way".
And I'm not saying this happens everywhere but it is common.
My suggestion is: call the italian store before coming to Italy and ask for the price. Then compare it to the french price.
Have a good shopping weekend!
Bye
Brina