Nuclear energy operator EDF has shut down two reactors at Chinon in western France after a fire in a non-nuclear sector of the plant in the early hours of Saturday, the company said.
The fire has been extinguished, it said.
"Production unit number 3 at the Chinon nuclear power plant has shut down automatically, in accordance with the reactor's safety and protection systems," EDF said in a statement, adding it also shut down reactor number 4, which is coupled to number 3.France's nuclear safety watchdog said in a separate statement the fire had led to an electricity cut at the plant that triggered the automatic shutdown.
Chinon is one of France's oldest nuclear plants.