In the video, obtained by news agencies in Afghanistan, the dirt-streaked man barely seems to open his eyes as he pleads for his release.
"I have been here for the last eight days, fully in the black," says the hostage, who identifies himself as Dany Egreteau.
Egreteau was captured by gunmen in Kabul Nov. 3 as he drove to work with another aid worker, who managed to escape. An Afghan who tried to prevent the kidnapping was killed.
It was unclear when the video was taken, although Egreteau's statement suggests it was shot just over a week after he was ambushed.
His voice trembled at times. He refers to a ransom demand, begging for someone to pay it off.
A French official said authorities confirmed that the video showed Egreteau. The official would not comment further and spoke on condition of anonymity because of the sensitivity surrounding hostage-takings.
Security has deteriorated across Afghanistan over the last two years, and the capital, Kabul, has seen a spike in crimes against Westerners in the last several weeks.
Last month, a British-South African dual citizen aid worker, Gayle Williams, was killed by Taliban gunmen while walking to work. Also, two employees of the international shipping company DHL, one a British citizen and the other a South African, were killed by a gunman outside their office.
Egreteau worked for Solidarite Laique - or Secular Solidarity - which describes itself as a not-for-profit group working to promote education and health care, among other issues.
At the end of the tape, the camera pans down to Egreteau's dirt-caked fingernails and the chains. His captors are not visible.