Why was the French monarchy so wealthy and powerful?

They taxed the hell out of the people.

Fixated on wealth today are we? : )

The “wealth” was largely illusory. Throughout most of the Bourbon dynasty, France (and in those days, the king was France) ran a gigantic deficit. The kings dissipated the treasury by waging costly wars and maintaining a lavish lifestyle. In fact, they were spending borrowed money.

One of the causes of the deficit was that the segments of society where the wealth was concentrated—the nobility and the clergy—claimed exemption from taxation. That shifted all of the tax burden onto those who were least able to pay. Deja vu, anyone?

Louis XllV was very shrewd about taking power from the French aristocracy. He removed the nobility from their traditional provincial centers of power and forced them to become sycophants of the French court at Versailles. Everything was regulated by a very strict protocol.Power was achieved by playing politics of the court and the rules were set by the king. I am certainly no expert at French history but I read this historical background in the book Apollo’s Angels-A History of Ballet.
More details from Wikipedia
http://en.wikipedia.org/wiki/Palace_of_Versailles

I found this account of how Louis XIV further solidified the power of the monarchy.
http://www.historylearningsite.co.uk/louis_xiv_and_domestic_policy.htm
It is somewhat ironic I think that the French nobility was restricted from engaging in “commercial and manual activities” with a few exceptions. They were exempt from the land tax, which the peasantry with land had to pay, called the taille.
http://en.wikipedia.org/wiki/French_nobility
In order to maintain their postition in court they were all but forced to engage in spectacles of conspicuous consumption.