So what pod is required for France to be able to resist and eventually push back the german invasion?
Technically following the OTL lines of technological and military development, France always was behind Germany in all aspects. (at least in the period refering to the WW2.) Only the French Navy was comparable in level of technology and superior in numbers.
To have France survive the German attack of may 1940, something else than france itself had to accomplish that, possibly a sudden attack of teh USSR on the Eastern border, even if that was futile, given the contemporary Red Army following the timeline. (USSR was only read for war in 1943, not before). It could however draw away enough German military resources to have the Advance of the German West front stall enough to have it becomming a repeat of WW1. If the Allies could have brought enough military power in the Low Countries adn Northern Fracne, and the USSR could draw away enough of the German Wehrmacht, things in France might have looked better, though all would depend on wether the German leadership was bold enough to take the bait, as the Intelligence all to well knew about the weaknesses of the Red Army in may 1940, believing it to be inferior to the German Army of the time. Theoretically the Germans could allow the Russians to advance for a while, concnetrating on the destruction of France as primary adversary on land for the time, later on pushing back the Russians.