I live in France, have done for far too many years, and I think I know a bit or two about them. I agree with most of what has been said above, but there is one more thing you need to know about - the French national character.
On a personal level, imagine you accidentally bump into someone's foot with your trolley in the supermarket. Being a well-brought up Brit, Aussie, Yank, etc, you apologize, expecting them to shrug it off, and say no more; instead, the French person begins to have a verbal go at you, as if you had done it deliberately.
Second scenario. You drive normally through a green light, and are rammed by a French driver, who is probably drunk to boot. He starts shouting and waving his arms, not always politely, and tries to blame you.
Your French colleague fails to attain his objective at work. Instead of, "OK, I'll give it another crack", you get a list of (usually feeble) reasons and things beyond-his-control to try and shove the blame onto other people.
See where this leads? Exactly. They are a nation of whingers who would blame anything on anybody, regardless of the rights and wrongs, just as long as they don't have to admit they fluffed it. Of course, some individuals are nice, straight types, but on the whole, forget it. And as for admitting that they simply folded owing to poor training and worse leadership, both military and political, drop that!
Incidentally, just to give some authority to the above, I'm also involved in developing the Combat Flight Simulator 3 Battle Of France add-on - which started simply from wargaming the French Campaign, and coming to the conclusion that with more aggressive leadership and more effective soldiering, the combined forces could have given the Germans a really nasty ride - even if we have never actually had the Allies win.