Remains of 351 stillborn babies and foetuses have been found in the mortuary room of a well-known hospital in the French capital, Paris.
All relevant French hospitals will now be checked
Some of the tiny bodies had been kept against regulations at St Vincent de Paul for up to 25 years and the government has ordered an inquiry.
Health Minister Xavier Bertrand said his ministry would try to find out why and how it had been allowed to happen.
All French maternity hospitals linked to mortuaries will also be checked.
The public prosecutor's office in Paris has opened its own investigation into the case.
Announcing the grisly find, Xavier Bertrand said he was sad and indignant.
"I want to share my deep emotion and indignation at this discovery," he said after visiting the hospital in southern Paris.
"This situation demands that we find the truth."
French health ministry guidelines require that hospitals incinerate stillborn babies whose bodies are not claimed by relatives within 10 days, Liberation newspaper reports.
The BBC's Caroline Wyatt reports from Paris that French commentators suspect similarities to the Alder Hey scandal in the British city of Liverpool.
Parents there discovered that the remains of their children had been kept by the hospital without their consent.