BORDEAUX (AFP) - French prosecutors launched a murder probe on Saturday into one of the country's worst cases of infanticide after five dead babies were discovered in a home near Bordeaux.

A 35-year-old mother was hospitalised in a psychiatric ward after police on Thursday found the bodies in her house - four of them in a freezer.

Her 40-year-old husband, a farm worker, was charged Saturday with failing to report a crime and possession of the body of a homicide or involuntary manslaughter victim.

He is believed to have known about the baby corpses in the freezer.

However, it was the father who found a thermal bag containing the corpse of another baby early on Thursday at the family home and alerted police, a source close to the investigation told AFP.

The child is thought to have been born Tuesday night and - according to one of the mother's rare statements to investigators - "the baby was born viable," deputy prosecutor Anne Kayanakis said on Friday.

Investigators subsequently discovered the bodies of four other babies in a freezer at the home in the south-west of the country. The parentage of the children was still being confirmed via testing.

The mother apparently "gave birth at home alone", the source said.

According to prosecutors, the family, which also included two girls, 14 and 17, did little to attract attention to itself.

The worst case of infanticide in recent French history dates back to 2010, when a mother admitted to killing eight of her babies, smothering them immediately after they were born.

Another French mother was jailed in 2009 for smothering two boys born in secret when she was living in South Korea, and a third child born in France. The bodies were also stored in a freezer.