Six people have been killed and more than 20 injured in a train crash at Bretigny-sur-Orge, south of the French capital Paris, officials have said.
The intercity train had just left Paris and was heading towards Limoges when it derailed, crashing into a station platform at 17:14 (15:14 GMT).
Passengers were left trapped inside carriages.
French President Francois Hollande visited the scene and expressed his shock at the accident.
Six people died and 22 others were seriously injured, Mr Hollande told reporters. All those with serious injuries were now in hospital, he added.
He spoke of his "solidarity" with the families of those caught up in the accident, saying that the station would be closed for three days while investigations were carried out to determine what led to the derailment.
The French rail company SNCF said 385 passengers were on board when it crashed. The station platforms were crowded at the start of a holiday weekend.
"Shortly after departure, just as I was getting into my book, we felt a first shock that shook the carriage I was in.... Then there was a second shock and the carriage lifted up, then a third and a fourth and the carriage went over on its side," passenger Marc Cheutin told the AFP news agency.
Other media reports spoke of passengers being electrocuted and crushed.
"I saw many wounded women children trapped inside," Vianey Kalisa, who was waiting for his train from Bretigny to Paris, told AFP.
"People were screaming. A man had blood on his face. These are images of war," he said.
Bretigny mayor and local MP Michel Pouzol said four of the carriages were lying wrecked on the station platform.
He said the emergency services responded to a "red alert", put into action when many casualties are expected.
Guillaume Pepy, president of SNCF, described the accident as a "catastrophe" and explained that the train's third and fourth carriages derailed first and the other coaches followed.
Ophelie, who witnessed the crash, told the I-Tele news channel everyone was shocked and some people on the platforms were among the injured.
French transport routes were particularly busy at the time of the crash due to the run-up to a holiday weekend marking Sunday's Bastille Day.
"There were plenty of people on the platforms because of it being a holiday weekend," said Jean Paul Huchon, Socialist president in the IIe de France area.
