France's President Emmanuel Macron condemned "unacceptable" lapses within the judicial system on Friday over an 11-year-old girl's killing, after it emerged that the main suspect was previously accused of sexually abusing children.

A girl, named in the press only as Lyhanna, went missing on 29 May near the southwestern town of Fleurance after she was last seen getting into a man's car.

After days of combing the countryside, investigators found the body of a child wearing the same clothes as her in an abandoned silo in the nearby village of Puycasquier on Thursday. Formal identification is under way.

A 41-year-old father of two, whose daughter was a school friend of Lyhanna, has been detained as the key suspect.

It emerged he had twice previously been formally accused of raping a child, but the investigations had either been dropped or stalled.