Maybe there was no cowardice by the common man in France. But there was plenty of cowardice in the government leading up to the invasion of France in WW2.

For example, not helping allies (like Poland) that they committed to helping in treaty.

They could have easily stopped Hitler if they had the will before the war. The German generals even said so. They were ready to depose Hitler over his rash actions. But Hitler was right about all of the western democracies (France, England, and the US) and they did nothing when he went in and bullied the smaller countries around him.