Pickpocket... Hero: Thief saves sleepwalker from metro tracks after robbing him (VIDEO)

French authorities have released CCTV footage from the Paris Metro this week that has left people to ponder over what it is that makes us human.

The footage aired by France 5 on December 8 shows the change in character of a pickpocket, who after robbing a sleeping man returns a short while later to rescue him after he sleepwalks on to the metro tracks.

After spotting a man asleep while waiting for a train, an opportunistic pickpocket approaches his victim and then pilfers a number of items from the man’s pockets, before fleeing the scene.

Shortly after, the unaware victim rises to his feet, still asleep, and starts to stumble towards the platform’s edge.

Another bystander watches but does nothing to stop the sleepwalker from falling on to the tracks. The bystander simply turns his back and walks away.

A train then pulls into the station, narrowly missing the man on the tracks.

In an unlikely turn of events, it is the pickpocket who rushes back to the scene to help the man off the tracks.

Emmanuelle Oster, chief of investigations for Paris transportation, who narrates the video in French, marvels at the "paradox" of the thief returning to aid the man while a bystander watched him fall and did nothing to help.

"He knows he’s a thief, and maybe that makes him a bastard," Oster says. "But he isn’t so much of a bastard as to let this guy get electrocuted on the tracks."

"There’s a philosophical lesson to be learned here," Oster adds. "Inside every thief there’s a human being, and in every innocent bystander there could be a bastard."