Amedy Coulibaly, the gunman in the kosher market, could be heard asking hostages their names and where they were from during his rampage, according to the French weekly newsmagazine Le Nouvel Observateur, which cites newly available video of the event.
The video was recorded by a GoPro camera hanging from Coulibaly's jacket, the magazine reports. The seven-minute, 45-second video is in the hands of investigators.
It shows Coulibaly grabbing a man, and then shooting him dead after learning his name, the magazine says.
Coulibaly grabs another hostage and asks him where he's from, shooting him after the man replies: "Jewish."
Coulibaly then says, "You know why I'm here, then! Allahu Akbar! [God is great]."
The magazine reports that Coulibaly seemed to have trouble reloading his Kalashnikov automatic rifle, and he sought the help of his hostages in transferring the GoPro video to a computer.
In a related attack hours earlier, two brothers killed 12 people at the offices of Charlie Hebdo.
The Charlie Hebdo shooters, brothers Said and Cherif Kouachi, were both killed by police as they attempted to flee. Coulibaly was killed two days later.