So all the online prices at the Louis Vuitton website include taxes that means the prices for France and Italy should be different right?
Both France and Italy are members of the EU so all prices are in Euros. I believe the prices are the same. A Neverfull MM costs 845 Euros in either country. You can look up prices on the website for any country, just change the country location. (It's at the bottom tool bar.) It's pretty easy even if you don't speak the language as the format is the same as the US website.
ETA: The VAT refund is likely slightly different for each country so depending on what % is refunded by Italy and France, one or the other might be slightly less expensive after the refund. Honestly, at this point, you're talking maybe 1% or 2%.