Update from my side: thanks to a great user of the forum, i managed to contact the owner of the shop.
He said that my order was shipped but lost. In any case he offered me to re-ship or refund, at which point i chose refund, which arrived quite promptly, i must say.
All in all, it turned out well, and Frederic seemed to be a pretty OK guy. I can't tell if, with me doing nothing and just waiting, i would have received anything in the end.
My conclusion is that, now that i have the contact, i could try to order again (maybe) from him.
Without, i would personally avoid international orders for items not currently in stock, and, more in general, recommend to use the shop (which still has an interesting selection of products, in my opinion) to the locals or to those who could, in case of problems, use an holiday to Paris as last resort :-)
And i want to again those here who helped me! Thanks for the help guys! :-)