Police officers discovered the corpse in the women's shared home in France's Brittany town of Mael-Carhaix on Friday after authorities expressed concern about the home's state of neglect, according to the local paper La Telegramme.
Police were called to intervene when neighbours complained of rubbish being left in the garden for "years" and after bills had gone unpaid, The Independent reported.
The police said that when they arrived the woman seemed "confused, delirious and incoherent".
The mother and daughter had reportedly lived in the village for the whole of the latter's lifetime, and local mayor Michel Henry told news outlet Ouest-France they were seen as "recluses".
More From This Section
Henry said it was "an unthinkable tragedy for our time". The prosecutor said the daughter had been taken to a psychiatric hospital after she was deemed too confused for questioning.
Police said that it was too early to say if she had died of natural causes.