Louis began his personal reign with administrative and fiscal reforms. In 1661, the treasury verged on bankruptcy. To rectify the situation, Louis chose Jean-Baptiste Colbert as Controller-General of Finances in 1665. However, Louis first had to neutralize Nicolas Fouquet, the Superintendent of Finances, in order to give Colbert a free hand. Although Fouquet's financial indiscretions were not very different from Mazarin's before him or Colbert's after him, his ambition was worrying to Louis. He had, for example, built an opulent château at Vaux-le-Vicomte where he entertained Louis and his court ostentatiously, as if he were wealthier than the king himself. The court was left with the impression that the vast sums of money needed to support his lifestyle could only have been obtained through embezzlement of government funds.
Source: Wikipedia