On Rue de Sebastopol in the second arrondissement of Paris, the local Monoprix supermarket is playing host to what could be the city's archaeological find of the year.
Builders adding extra storage space to the basement made the grisly find, calling in archaeologists from the National Institute for Preventive Archaeological Research (Inrap) to take over.
The team found the bones of men, women, and children - stacked up to five bodies deep. They reported finding eight chambers with around 200 bodies in total.
(Photo: Denis Gliksman, Inrap)
"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," store manager Pascal Roy told the AFP news agency.
The supermarket was built on the site of the Trinité hospital.
Experts said that as the skeletons were so closely packed together in a mass grave, it suggested that they were the victims of an epidemic like the plague, which struck France throughout the 14th, 15th, and 16th centuries.
Archaeologists say that the grave provides an excellent opportunity to learn about how death was managed and how funerary practices were carried out centuries ago.
The archaeologists wrote in a statement that they would carry out carbon and DNA testing on the bones to find out more.