Fire blocks major Paris station at height of holiday exodus

A major fire in the Paris suburbs paralysed traffic in and out of the city's Montparnasse train station today, just as thousands of French travellers head off on their holidays this weekend.

Photos and videos posted on Twitter showed a massive plume of smoke rising into the skies from an electrical centre run by the national transport network in Versailles, southwest of the city.

The blaze shut down traffic just before noon at Montparnasse, the main station connecting Paris to west and southwest France, with rail operator SNCF warning of heavy disruption for the rest of the day.

"Those who can delay their journeys need to delay them," Alain Krakovitch, a senior official at rail operator SNCF, told reporters at Montparnasse.

The station in southern Paris, which in the midst of a heatwave is sweltering in temperatures of 35 degree Celsius (95 Fahrenheit), was crowded with stranded passengers staring up at the departure boards.

SNCF official Patrick Jeantet said the electrical centre hit by the fire was a crucial site which controls Montparnasse's safety installations.

Authorities were seeking to reroute some trains to another main station, Austerlitz, he added.

The shutdown came just as the French capital empties out for August, when many Parisians traditionally head to the beach or countryside for much of the month.

Montparnasse station was the scene of similar transport chaos almost exactly a year ago, when a giant signalling failure caused three days of heavy disruption.

Travellers crossing between France and Britain were also suffering disruption Friday, as the heatwave prompted delays in the Channel Tunnel.