France demanded that Germany pay reparations after World War I. That worked well.
France remained in a state of war with Germany for 250 days. They watched Germany conquer Poland, Norway, and Denmark, and did nothing. France had the largest army in Europe at the time. On May 10, 1940, they watched a smaller German army invade Luxembourg, Belgium, and the Netherlands, and still did nothing. It is this fact that did not work out well.
If France had come to Poland's aid in Sept 1939, they at the very least could have marched to the Rhine, reoccupying the Ruhr, and threatening Frankfurt, Stuttgart, and possibly Munich. But they showed weakness instead. And this more than anything else led to the German onslaught over Europe.