A Metro train derailed at a station in central Paris on Wednesday, slightly injuring 24 people and just missing another underground train standing on the opposite track, according to the Paris transport authority, RATP.
Paris police chief Mr Philippe Massoni said it was a miracle no one was killed or seriously hurt.
The train jumped the tracks at a curve and the front carriage fell on its side, careering for 100 metres before stopping just in front of the other train, RATP chairman Mr Jean-Paul Bailly told a news conference.
Ten of the 42 passengers were taken to hospital and another 14 were treated at the scene. Mr Bailly said the worst injury was a broken limb, while the train driver was suffering from shock, but was only slightly hurt.
The accident occurred at 1:22p.m. at the Notre-Dame-deLorette station in north-central Paris, not far from the Saint-Lazare suburban train station and the big department stores along the Boulevard Haussmann.
The Paris Metro, which celebrated its 100th anniversary earlier this year, carries some four million passengers daily.
The last derailment was in 1996, but no-one was hurt, Bailly said.
Experts said it was not clear why the train jumped the tracks on Wednesday. An investigation has been opened.
RATP security chief Alain Caire said the train was supposed to have been travelling at 30 k.p.h. (19 m.p.h.). Experts would investigate whether it was speeding or whether a technical fault on the train or the track could have caused the accident.