Absolutely right to be skeptical. The regional demographics in many of these overlapped regions have gone through comprehensive changes over centuries under drastically different regimes. The map about English posessions in 1154 vs. first round of French presidential election is just an absolute straw-grasping joke. ~900 year's worth of cultural, demographic, and economic shifts reduced to basic visual pattern recognition AKA the thing that causes people to see Jesus on a piece of toast.
The map about Charlemagne's empire vs. 6 original members of the future EU is a joke too. The latter was a product of the reality of post-WWII European politics (Iron Curtain, Allied occupation of Germany and Austria, and Spain being a neutral country ruled by de facto dictatorship). It's fun to look at patterns and think they are neat. It is absolutely not fine to pretend these resemblances somehow have a direct & causal relationship without properly navigating the long and complex multi-faceted history behind them.
The map about Charlemagne's empire vs. 6 original members of the future EU is a joke too. The latter was a product of the reality of post-WWII European politics (Iron Curtain, Allied occupation of Germany and Austria, and Spain being a neutral country ruled by de facto dictatorship). It's fun to look at patterns and think they are neat. It is absolutely not fine to pretend these resemblances somehow have a direct & causal relationship without properly navigating the long and complex multi-faceted history behind them.