The UN child agency and non-governmental organisations on Wednesday urged France to better protect minors exploited by gangs for crime instead of prosecuting them.
"In France, children who are victims of criminal exploitation are too often prosecuted and punished for offences committed as a result of their exploitation," UNICEF said.
"But international and European law requires them to be recognised and protected as victims of human trafficking."
UNICEF pleaded for "a complete overhaul of (France's) treatment of minors exploited to commit offences".
Two-thirds of people exploited in France for crimes -- including drug peddling, theft, robbery, pimping and fraud -- are under the age of 18, according to government figures.
Ninety-two percent are foreign unaccompanied minors -- mostly from Algeria and Morocco, other parts of Africa and eastern Europe, according to non-governmental organisations who work with them.
Eighty-nine percent are boys or male teenagers.
Examples include young migrants in northern France manipulated into crime to pay to be smuggled across the Channel to England, or even Bosnian girls deployed into public transport to pick pockets under threat of violence from their minders, it said.
"Those who exploit them use different strategies: addiction, blackmail, threats, psychological pressure, violence," UNICEF's Corentin Bailleul told AFP.
"Exploited youth are often recruited under false promises, or forced to act to survive or repay a debt," he said.
UNICEF said France's criminal law needed to "explicitly state that a person who is a victim of exploitation cannot be held criminally responsible when the offence committed is a consequence of trafficking".
A collective of 28 non-governmental organisations called Together Against Human Trafficking backed the call.
"Police and the judiciary need to be trained so their first instinct is to consider them as victims and not as offenders, and to put an end to this double punishment," said its coordinator Genevieve Colas, urging rapid change.
"We used to have teenagers, now we have kids aged eight to 10 who are victims of trafficking," she said.