Looking at the last software charts from France. I would think it sells mostly there and maybe a mix of Germany/Spain ... otherwise, it's not a massive juggernaut elsewhere from what I know.
It still doesn't totally add up.
From what we have here (UK, France and Germany and all of Europe at July 7) it's 28464 for the Switch and 28394 for the PS4 when combining UK, Germany and France sales, so basically the same if taken together. Even in the UK, which is often considered Nintendo's hardest market, the PS4 only has a 3k or about 30% lead over the Switch. However for all of Europe, Switch is at 51k (so less than double) while the PS4 is at 85k (so more than triple). That would mean that Switch is mostly flopping outside of the big 3 (which especially on account of Spain and Italy over the last months doesn't seem like correct), but also that the PS4 is, relatively speaking, rather unpopular in the big 3 compared to the rest of the continent.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/