Snake Featherston
Banned
The French fought like Hell on Earth AFTER the cream of their army had been lost in Belgium. You can blame that disaster on their senior military leadership. It was simply, in France itself, a matter of defending in relatively clear terrain.
Plus facing air superiority, better training, blitzkrieg warfare, better tanks (French tanks were tougher but had practicality issues), and facing internal political dissension.
Read Will Shirer's "Rise and Fall of the Third Republic".
Oh, and after the Commune, no way do the French allow a battle in Paris.
More than that, it was a matter of the gamble of moving what reserves they had into a strike in Belgium that they had every rational reason to suspect would in fact be the German plan of operations. That's the kind of thing where in success it's brilliant audacity, in failure it's a sign of incompetent blunderers who didn't know what they were doing. Well, OTL was a failure and thus.....