The French government has released an online video designed to steer young people away from joining militant groups in the Middle East.
The two-minute video features hard-hitting scenes of conflict and execution.
It is part of French efforts to stop the recruitment of more youngsters, often via the internet.
More than 1,000 French residents have joined extremist groups to fight in Syria or Iraq or are planning to do so.
The release comes three weeks after attacks by home-grown jihadists in Paris in which 17 people were killed.
The video uses images familiar from jihadist websites such as scenes of jubilant fighters celebrating in Syria or Iraq.
'Hell on earth'
But the scenes of war-time camaraderie and moral victory are interspersed with darker images, showing a different side to the conflicts there.
Black and white footage of men being crucified, thrown over a cliff and dragged along behind a truck are overlaid with government messages, warning of "hell on earth".
Far from helping Syrian children, the video tells viewers they will be complicit in the murder of civilians and die alone, far from home.
Other messages are clearly directed at women. "They tell you come and start a family with one of our heroes", the video warns. "In reality you will raise your children in war and terror."
"We will broadcast this video widely on social networks in order to reach the maximum number of young people vulnerable to these calls. We hope it will shock them", the head of the French government's communication department Christian Gravel told Agence France-Presse.
The French government has battled for months against what it calls "terrorist propaganda on the internet".
The deadly attacks in France three weeks ago have refocused attention on the threat from home-grown jihadists many of whom are attracted to extremist groups over the internet.
The French interior minister has said he will meet major internet companies in the US next month, to try to find new answers to the problem.