A French woman, Josiane Vermeersch, who was attending her brother's funeral last week found the newly marked grave of her 42-year old son in the same cemetery, Reuters reports.
The family were leaving the cemetery near Lille, about 220 kilometres north of Paris, when one of them noticed a temporary wooden gravestone bearing the son's name and date of birth in an area reserved for poor people.
Ms Vermeersch said she had tried to contact her son a few days before the funeral to invite him but was unable to make contact. She thought he was ignoring her after a row.
She has demanded an explanation from the local council as to why no one in the family was informed that he had died on 5 July from natural causes.