From the Third Republic to the Popular Front, which tied together both Liberals and Socialists, France was very much divided politically.
The French were forced to surrender after many military defeats. The major cause of these victories of Germany is that
France's army was, overall, very weak and infested with problems.
When Hitler set his mind on conquering the nations of France the French army was no match for Hitler's war machine.
The Nazis possessed an amazing fighting ability, as the French were not agile and very slow moving.
The Germans also had very advanced tanks and, again, very good war tactics. The French also had armored vehicles and aircraft, but they were poorly managed. The French commanders were constantly confused, as for the opposing side, the German commanders were great leaders and were very decisive in their actions.
These conditions made the morale of the French very low.
I will also argue the point that the intelligence of France was not well organized and very inefficient.
They were also not good at relaying this information to the correct people and transferring it into policy.
Also, French intelligence was not good at analyzing or interpreting the information they received.
France did not have any strong alliances before the invasion.
A major reason for their defeat is that the French could never exactly pin down where the main thrust of the German army would come from.
This sometimes left the best soldiers against nothing, while the worst soldiers were against the core of the German war machine.
On June 22, 1940 France surrendered to Germany after a six week invasion. If it weren't for these major problems of France they could have very possibly defeated Germany and ended this war. These constant military defeats were caused mainly by the weak military of France. The German tactics and weaponry were far ahead of the French and this included their intelligence abilities. The French could not properly organize or turn the information they received into policy. All these points, and more, cumulate to create the causes of why there was no fight in France and why it fell so swiftly in 1940.