They lost 1.7 million men in WWI (more than we’ve lost in all of our wars combined) - but they themselves acknowledged that they didn’t breed enough afterwards (they themselves were quoted as saying “not enough babies”). Germany had lost a similar figure, but replaced them better.
I did not know that. I thought it was due to the blitzkreig tactics that simply overran them. They were too reliant on the old Maginot Line.