I just saw this on Gonintendo so I thought I'd link it here.

https://gonintendo.com/stories/375489-nintendo-france-shares-stats-on-switch-hardware-and-software-sale

A few things stood out.
4.7 million people own a Switch in France now.
51 Worldwide games outsold Ring Fit Adventure, Hyrule Warriors and Paper Mario The Origami King.
The switch has had a 40% growth over 2019.

The 7% figure for Switch attach rate in France is likely a rounded figure, so it leads to some uncertainty around the total sales in France.

So looking at the source it sounds like they did an interview with someone from Nintendo France and were told that 7 % of French people own a Switch. Seems like a weird piece of information which is probably why they calculated it to an actual number of people, but that also means there's probably a notable margin of error on that number. Impressive nonetheless.

Also sounds like 51 Worldwide Games did insanely well in France if it outsold Ring Fit, which has been topping their chart often.

Is France the biggest market for the Switch in Europe? Do we know the sales per country?

7% is probably an estimation. If my memory recalls correctly an estimated 1.25 million switches were sold last year in France, a forty percent increase would put it at 1.75 million for the year. Combined with the figure for install base at 3.3 million at the end of 2019 you would net 5.05 million switches. This would have around 7.5% of the market share. Take all this with a grain of salt as most of my information is second hand and based off of my memory which could be wrong.

~1.5M million Switch is around UK number which is weird since France market is stronger for Nintendo than UK. With the increase sales from Covid i think ~40% increased YoY is much better indicator than population percentage comparison.

Interesting that Clubhouse Games did so well in France. There is probably a potential untapped market for this game in a lot of other countries. Perhaps from non-traditional gamers?