France's top constitutional body struck down a 75-percent upper income tax rate on Saturday, dealing a major blow to Socialist President Francois Hollande, who had made it his centerpiece tax measure.

The government vowed to push ahead with the tax rate, which would apply to incomes over a million euros ($1.3 million) a year, and propose a new measure that would conform with the constitution.

The tax rate had angered business leaders and prompted some wealthy French citizens to seek tax exile abroad, including actor Gerard Depardieu, who recently took up residency in Belgium.