>France is mostly empty

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.

It's mostly a matter of when the demographic transition started: https://nitter.net/pic/media%2FGEDBLvOXUAANUlK.png%3Fname%3D...

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).

More data on that piece of history, and a hypothesis to explain it, here: https://worksinprogress.co/issue/frances-baby-bust/

> 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.