noblejoel, the French Army was consider (though wrongly) the most formidable army in the world before the battle. I believe they were also much larger when the battle began, and also had the support of the BEF and other nations.
On paper, it would look like the French should win, but they were only like a thin eggshell of what they seemed to be. Their military doctrine was very out of touch with the times, and they had no idea how to properly use their new equipment. Discipline in the French army was also very poor, and the men often neglected to salute superiors, often shirked duties, and often did not even wear uniforms properly.
I don't mean to be offensive to anyone, but the French army has never really had a reputation for being very disciplined, or particularly brave. I can't think of a time, after the Napoleonic wars, that the French were really feared or considered a real threat to their enemies. Ever since Napoleon's reign, France has not been a very "miltaristic" nation. They've seemed to avoid conflicts (for the most part), and enjoy civil life more than military life. They've certainly won battles and mounted heroic efforts in conflicts, but for some reason they have developed this sort of reputation about their military being lax on discipline and the men not taking it very serious. They certainly had not taken the German threat serious enough before WWII, and they suffered the consequences.
The "Battle of France" was extremely important to the evolution of modern combat. As other's have said, even modern campaigns, like "Desert Storm" and "Iraqi Freedom", used classical Blitzkrieg tactics. The fact that a nation that was once in shambles rose up to defeat, in only six weeks, what was the largest and considered the most formidable army in the world, atests to the brilliance of the concept. This was in the days before Hitler overbearingly meddled in military affairs too much, and before he began undermining the effectiveness of his own forces. This was when brilliant German commanders were able to show their skill and resourcefulness, without being second guessed by crazed, fanatical, and delusional politicians.
Grahame, I would like to mention that Hitler actually wanted the army to halt long before Arras. He felt that the fast moving Panzer units would get too far away from the infantry and their supply columns, and he actually ordered his commanders to halt for them to catch up. However, seizing the initiative, the commanders disobeyed him and pressed forward, totally splitting the enemies' forces in two. Under normal circumstances, he would have brutally punished disobedience, but he was so pleased with the results that he actually praised the commanders (that is, just before he convinced himself that it was his idea all along! LOL!). The Germans could have, very likely, totally decimated the BEF at Dunkirk if they had seriously attempted. However, Hitler really wanted to have the British sign a peace treaty. He wanted conflict in the west to end, thus freeing his forces up for his ultimate dream of conquering the Soviet Union. He actually admired the British empire. He felt that if he ruthlessly slaughtered their troops at Dunkirk, while they were trying to withdraw, that he would be hated even more by the English and that they would never sign a peace treaty. So, the Luftwaffe was tasked with destroying British equipment at Dunkirk, and they were told to try to avoid killing the men. But, what Hitler thought was some "charitable act of mercy" was not seen as such by the English. They remained defiant of Hitler, and that lead to the "Battle of Britain". That's another story in itself, but feel free to check out my post in the BoB section in which I explore that conflict in further detail and address many historical myths surrounding it.