Never said that. They did well until post-WW1. Must have been the mustard gas that sucked the backbone right out of the French after all that.
frenchie military victories since WW1 have been pretty pathetic ... Vichy france, den bien phu, algeria ... really good track record there.
After the carnage of W.W.I, the French became more averse to war. You're probably right about that.
In W.W. II, the French (like everybody else) was expecting a repeat of German tactics from W.W.I. They were prepared for that kind of conflict but the Germans had a new type of warfare in mind. This took the French, and much of the rest of the world, by suprise. Remember also that Poland was effectively defeated by the Germans in 19 days while France was also defeated in a realtively short time, six weeks.