I checked some quick numbers and Lidl is around 10% in the French market, while Aldi is around 4%. They've both surged since Covid. In 2010 together they held about 3% of the French market.

So yes, there are more recent developments for supermarkets, but repeat the exercise for banks or other fields. How often do French people get services from German companies, for example online retail? Do they go to otto.fr, kaufland.fr, etc?