"Public" is one of the two biggest tech shop chains in Greece. They are the first to set up preorders following announcements and they also do get us the collectors editions of most games before any other shop.
They posted this on their page, with a placeholder price at 399 Euros. There is a clause though, saying that if the final price is actually lower, they will charge the lower, official price and not the preorder price.
"Public" and "Plaisio" would definitely be in the meeting that allegedly took place in EU a few weeks ago, since all other shops/chains in Greece are much smaller than those two. Public even removed the WiiU from their stores and online recently.
To give you a perspective of prices in Greece, the WiiU premium console + Mario Maker costs around 300 Euros here.
I am not saying this is proof or indication, or anything, and surely the preorder price could be just their safe bet, but they could have just launched the preorder with a blank price instead.