score:6
In key areas, the German army was better. After Versailles, Germany was limited to 100,000 troops, and they were prohibited from cycling lots and lots of conscripts through basic training (that was a lesson of WWI and the Napoleonic wars).
Meanwhile the French built the Maginot line. Contrary to public perception, they did not expect to hunker behind those bunkers. It was supposed to defend their right flank while the mobile forces assembled on the left flank, for a battle through Belgium and the Netherlands.
When Germany won the battle in the Low Countries and broke through to Dunkirk, France didn't have the mobile troops left to stop a strike into their industrial and population centers.
(Side note -- one could say that the same factors contributed to the German defeat by the Soviet Union. Germany was prepared for short, decisive campaigns, but not for the long run.)