France is mostly empty by Europe's population density standard though, so even though it was likely not the intent of GP, it kind of works in that context.
Which is so weird! France has large amounts of good farmland, some of the most modern (and unified, unlike Germany) government in Europe for a long time etc... no obvious reason to have just half the population density of Germany.
France used to be “the China of Europe” (which is why we kept being at war with the whole continent at once). Had France followed their neighbors' demographic, it would be home to more than 200 million people today.
The demographic collapse of France in the 19th century, while Germany kept growing, alone explains the French defeat in 1870 (and then the two world wars).
> no obvious reason to have just half the population density of Germany.
France was historically always focused on Paris, because that was where the Emperor was. If you were not a farmer, there was little reason to live anywhere but Paris or other large cities.
In contrast, Germany historically consisted of thousands of small fiefdoms that each held some sort of local importance and each held authority of some sort. The Kaiser was pretty far away and only mattered in practice when the Kaiserreich was involved in some sort of conflict.
> France was historically always focused on Paris, because that was where the Emperor was.
So much misconception in such a short sentence…
First of all France only had an “Emperor” for a few decades (10 years for Napoléon 1er, 17 for Napoléon III).
Then, Paris wasn't even the King's main residence for a good part of French Monarchy (the Loire valley (hence the list of famous castles here) and Versailles both aren't Paris).
Centralization around Paris built up progressively, but it's really the French revolution (which came with the suppression of the old regional Parliaments) which made modern France the way it is. And the US is the only place where you can claim that 200 years of history counts as “always”.
As I said in a comment sibling to yours, this has nothing to do with political organization, it's a consequence of demography: French people just stopped having babies one century before other European countries (and two centuries before the rest of the world).
That's a tough question, really. AFAIK the causes of the demographic transition in general are heavily debated among specialists and if we cannot exactly pinpoint what's driving the decline of birthrates happening right now, it's going to be even harder to pinpoint the causes for something that happened more than two centuries ago.
Which is so weird! France has large amounts of good farmland, some of the most modern (and unified, unlike Germany) government in Europe for a long time etc... no obvious reason to have just half the population density of Germany.