http://www.gameblog.fr/news/43423-france-mario-kart-8-booste-la-wii-u-nous-avons-les-chiffres
On my phone so using google translate is difficult. Basically says that MK8 made the Wii U sell 10 times as much as it did last week in France (apparently about 20k). So the Wii U sold more in France then Japan?
Btw. I didn't translate the article, someone on Gaf said this, so don't blame me if its false. :D