The European Union's top court backed Tuesday a lower court's annulment of a European Commission decision that had ruled French utility Electricite de France SA (EDF.FR) had enjoyed state aid in the form of a tax concession worth EUR888.89 million.

"The Commission erred in law by refusing, simply because the measure was fiscal, to consider whether the French state had acted as a private investor," the Court of Justice said in a statement after a ruling issued in
Luxembourg , where it is based.

On Dec. 16, 2003, the commission--which has executive and antitrust powers in the EU--ruled that EDF had enjoyed a tax concession corresponding to the corporation tax that the company didn't pay in 1997 when unused provisions created for the renewal of a high-voltage transmission network were reclassified as capital in the balance sheet.

However, in December 2009, the General Court annulled that commission's decision at the request of EDF, on the basis that the commission had failed to examine whether the French state had merely acted in the manner of a private investor, taking into account the whole of the operation of the restructuring and the fact that the French state was the sole shareholder of EDF at the time.

On Tuesday, the Court of Justice confirmed that annulment.