The bodies, which were found neatly stacked five deep in eight underground chambers, are thought to be victims of an epidemic that struck France at least five centuries ago. 

Archaeologists from the National Institute for Preventive Archaeological Research (INRAP) were called in to take a look and have spent days tirelessly uncovering the bones.

They found seven chambers containing around 20 skeletons each and a further chamber that had another 150.

Pascal Roy, store manager of the Monoprix supermarket, said that the shop had been built on the site of the old Trinité hospital, which functioned from as early as the 12th century. 

He said: 'We figured there'd be a few bones there considering it used to be the site of a cemetery, but we didn't expect to find mass graves.' 

But other experts have said the bodies might have been placed there when more than six-million corpses were moved to the Paris Catacombs from the city's cemeteries 200 years ago

Experts called the site 'extraordinary' and said they were astonished to find so many skeletons in one place.

They said: 'The fact that the skeletons were so closely packed together in a mass grave suggests that they were the victims of an epidemic like the plague, which struck France throughout the 14th, 15th and 16th centuries.

'The grave provides an excellent opportunity to learn about how death was managed and how funerary practices were carried out centuries ago.' 

Isabelle Abadie, an archaeologist, added that it was particularly interesting because the bodies were not thrown into the graves, suggesting that they might have been placed head to toe to save space. 

(dailymail.co.uk)