State-run utility EDF, a parent company of Enedis, is racing to get nuclear reactors hit by corrosion problems back on line.
The mayor of Paris Centre, Ariel Weil, confirmed the general breakdown on Twitter. "Power cuts have just taken place in the 4th and 5th arrondissements," he said.
Later, Weil added: "I confirm a general breakdown but @enedis confident of a rapid return to normal everywhere."