Alright, we have news!
I have found a document tracing Hélène Renaud renunciation to the house because, as we had suggested (and thanks to Lise and Pierre) she was a nun!
She gave the house to her sister, as per her Father’s wishes in June 7th 1939. For some reason, the register was stamped on 1954 which is why it came under 1954 previously.
Who was Hélène Renaud? A nun from the congregation of the Hotel Dieu. She took the name Marguerite Marie, I will try to see if I can find a picture of her somewhere.
Closer to the goal!