Le Drian had received a leaked UN report in July that detailed the sexual assaults which reportedly took place at a centre for displaced people. The abuse allegedly began in December 2013, when French troops were deployed alongside a UN-mandated European Union and African Union peacekeeping missions.
Le Drian told Journal du Dimanche that he immediately gave the report to the courts and that an internal army probe into the matter was conducted and finished in August.
The allegations only emerged this week in British newspaper The Guardian.
A judicial probe is still open more than nine months after the ministry received the leaked report because it is a "complex investigation," Le Drian said.
A French judicial source told news agency AFP last week that 14 soldiers are implicated in a probe.
The French military has fallen under criticism for taking so long to investigate the abuses, while the UN human rights office has faced accusations of trying to hide the crimes from the public, which it vehemently denies.
The UN employee who turned the report over to French authorities has said he did so because he felt his bosses had failed to take action.
French President Francois Hollande has pledged to show “no mercy” if the accusations turn out to be true.
Le Drian told Journal du Dimanche that ”when a French soldier is on a mission, he is France".
"If one of them has committed such acts, they must immediately give themselves up," he said.