In 2001 dustmen in Rueil-Malmaison, just outside Paris, were intrigued by a package dumped by a women who said she was clearing her cellar and told police, who took it to the local museum.
Staff there found that it contained a small coffin containing the body of a child.
After it had been X-rayed by a local vet and passed through a scanner, it emerged that it contained the preserved corpse of a five-year-old girl.
Experts from the prestigious Louvre Museum were alerted and declared that it was an authentic ancient Egyptian mummy of a child who had died between 365 and 170BC.
Inscriptions revealed that she was called Ta-Iset, was 92.5cm tall, had been well embalmed and was in good condition.
She will go on show in a specially adapted room in the Rueil-Malmaison museum next year.
It is still unclear how Ta-Iset ended up in France.
Mummies were brought to Europe in the Middle Ages, usually to be ground down for use in medicines.
But there was a real outbreak of Egypt mania in the 19th century when Napoleon Bonaparte invaded the country, taking archaeologists and scientists with him.
Many well-off households acquired Egyptian antiquities and a ring on the mummy indicates that it may have been on show in a middle-class salon.