Well in WW2, they were simply overrun by the new german strategy, although they outnumbered the germans and had stronger armor, basically then all the germans had were panzer 1, 2 and 3. I think they had some 4's too but not nearly enough to make a difference
The reason they lost though was the lack of strategy of their generals, as they were still thinking WW1 strategy, not the new one

So they were just unlucky that they lost paris so soon and capitulated, as I think if the fight would last a bit longer they would make a better stand

Now in Napoleonic time, they were the masters, their only problem was that everyone else was against them :S. But even so they kicked a lot of other europe nations armys arses

Which is funny since this was almost immidiatly after the revolution, where they suffered quite some casualties in civil and army sector

I wouldnt dis the french so much though, the real LOOSERS of all wars are the Italians, I mean they ALWAYS lost. In S Africa they got ass-kicked by the british who had 10 times less men than the Italians :S They also screwed Hitler when they attacked in the Balcans and got ass-kicked there too, so Hitler had to delay his plans to invade Russia for a few cruical months, where we all know what winter did to his troops

It is funny though that after both world wars they changed sides in the moment they were invated and ended up as winners, so they didnt pay any consequences :S
But thats besides the point, I still think Picard would win