Madame Lewanski

History
Madame Lewanski witnessed the flood 35 years before the events of season 1, along with Milan, Lucy, Madame Costa, and her son, Louis.

After the flood, she is seen looking for Louis. A few months later she visits the Costa's house with Louis, moments before Madame Costa's death.

She was murdered in her home a few months after the flood, along with her two sons. Her husband survived the attack.

Season 2
Madame Lewanski returns and is brought to her son, now known as Victor. She and Julie often get into debates on how to raise Louis/Victor.

Like many other returned, she does not remember how she died, only that she was in her house at the time of her death.

Later she is reunited with her other son.