Most of the countries that we look at today are rather different from how they were in the past. Territorial borders, for example, didn't become so important until people settled in a particular area, improved it and stayed there. Prior to that, territorial borders were fluid, based on how much you could hold, to a large extent. Language families and lifestyles bound proto-national groups together, rather than territory. Conquering tribes tended to settle in an area, and once they'd improved and upgraded it, wanted to stay. When this sort of thing became the norm, you got the idea that formed the seed of the concept of nationhood. Very rarely did it work, but the idea was there, and in different places at different times.
The major empires all used this type of thinking, but when they decayed, and when invading tribes came through, that idea was lost. Babylonians, Egyptians, Assyrians, Greeks, Romans - all had it. All but the Greeks and Egyptians lost it. Same with the Byzantines, though they started off while the Roman empire was on the way down. The barbarian tribes that moved into these territories did not have it, at least not at anywhere near the same level.
France under Charlemagne regained it... then partially lost it after his death. They were, however, largely insulated from the westward push from the tribes from the Germanies. That gave them a big advantage as nations started to coalesce later - a relatively unified language and territorial base. This was weakened when the Normans managed to successfully invade England then declared it to be their own, but had largely recovered by the time the fight for control over the Italian peninsula between France and the Spanish hotted up. France was usually a major power on the continental stage, except for those times when they were weakened by infighting or wars against other powers. They were still capable of major actions which took multiple countries to stop (under Napoleon, for example).
Probably the deathknell for France as the pre-eminent power in Europe came with WWI. Until then they were still one of the big bads on the block, but after the Germans punched through Belgium into France while the French cabinet dithered and refused to approve their military's requests, their reputation suffered a blow from which it never recovered. WWII similarly did them no favors, especially as they had better equipment than the invading Germans but lost the psychological battle. The Suez affair confirmed what everyone already knew - the French were no longer a 1st class military power.
The European Coal and Steel Community was an attempt to bind the armament production capacities of France and Germany together to prevent war, and was thus an admission that France could no longer compete with the Germans militarily. The ECSC became the EEC, then the EU. At heart it is still an attempt to bind together countries to prevent war.
Okay, a huge rambling preface for my main comment:
The Nobel Peace prize was awarded to the EU for simply doing its job. Which does rather detract from its original purpose.