First, I would recommend you listen to my podcast I did a couple of weeks ago.

Generally, I can say without reservation that France was a major power in Europe. In this post I made a while back I explain why France was in a good position in the 18th century. However what I do not include is the importance of the King of France in developing France into a major power. (Again, please look to the podcast)

After the French Revolution, France is weakened and left to a shadow of her former power. As a result, Prussia was able to go forward and start to unify Germany. However until the rise of Napoleon III, France was left behind. With Napoleon III, France was able to project power better than under the restored Bourbons and Orleans kings, going into Italy to help their movement against the Austrians.

However, French power would be diminished again when Bismark bated the French into declaring war against the Prussians, causing the downfall of Napoleon III at Sedan. From here, I'd tag /u/elos_ for a rundown of pre Great War France.

However, France has always been a European power and even now has clout thanks to De Gaulle.

What about Great Britain?

Supplemental Question time. Would it be wrong to go as far to say France was the leading European power from 1453 to 1870?