So she sold her properties, apart from two farms, one at Tocques and the other at Geffosses, the income from which amounted to no more than 5,000 francs, and moved from her house in Saint-Melaine to another, less expensive one which had belonged to her ancestors, located behind the covered market. (1.3)
An important part of understanding Madame Aubain's "haughty attitude" is understanding that she used to be rich and lost her home. Her new home, the one we get to see, is just not as good as what she's used to. The whole second half of her life is marked by loss, and that loss is symbolized in her home.
The interior was on different levels, and it was easy to trip up. (1.4)
This statement is so weird it has to have a second meaning. Why on earth would it be easy to trip just because a house is on different levels? Tons of houses are on "different levels" and that doesn't cause any problems. Maybe the levels represent something else; perhaps the class divide between Félicité and the rest of the family?
[Madame's bedroom] had pale, flowered wallpaper and a portrait of 'Monsieur' dressed like a fop, and communicated with a smaller bedroom containing two children's bunks without mattresses. (1.5)
The portrait of "Monsieur" is a painting of Madame Aubain's dead husband. We never meet him as a living character in the story, but his memory is an important presence in the home. Madame Aubain never remarries, and she hangs onto her identity as his widow, partially by decorating her home with his portrait looming over her bedroom. It's like he never left.
Her sadness had melted away in the warmth of her surroundings. (2.18)
When Félicité joins the Aubain family as their cook, she's not in very good shape. She's depressed over the deaths of her parents, her abusive employers, and her boyfriend leaving her for another woman. But the home life with the Aubains, with the love of the children and a place to belong, slowly heals her pain. Home is a powerful thing, apparently.
Whenever clouds gathered and thunder rumbled, he cried out, perhaps remembering the showers of his native forests. (4.15)
According to the story, Loulou comes from "America"; which could mean anywhere from Canada to Argentina. The idea that he would have memories of home is kind of interesting; it's a stretch from Normandy to the Amazon. But it likens him to Félicité, who's also out of place and far from her family.
This place, where few were admitted, was like a mixture of a chapel and a bazaar, full of religious objects and the most varied assortment of things. (4.28)
Félicité's room is like her little patch of earth. She lives in it for fifty whole years. The rest of the house is the domain of the Aubain family, but her room is hers. It's full of the things that she finds important, mostly religious objects and souvenirs. Her home, her room, is like the physical embodiment of Félicité's inner life, and boy does it look virtuous.
All the old things which Madame Aubain no longer wanted, she took for her room. (4.29)
We just talked about the importance of Félicité's room as her home; now we can see that the reason it's compared to a "bazaar" (in the prior quote) is that it's full of hand-me-downs. Félicité never has any money, so she doesn't buy things for herself. Her home is a borrowed room in a house, and it's filled with other people's belongings.
Madame's armchair, her pedestal table, her foot-warmer, the eight chairs: all were gone! There were yellow squares on the walls where the prints had hung. They had taken away the two bunks, with their mattresses, and in the cupboard not a single one of Virginie's things was left! Félicité climbed the stairs, beside herself with sadness. (4.44)
After Madame Aubain's death, it's unclear what Félicité's fate will be with regard to the family home. This is where it gets real; she might have lived with Madame for fifty years, helped to raise Paul, and basically run the household all that time, but when it comes down to it, the home is for the family, not the servant.
The next day, there was a poster on the door. The apothecary shouted in her ear that the house was for sale. (4.45)
When Félicité finds that Paul has put Madame Aubain's house up for sale after his mother's death, it's a shock not only because it is a change; it's also a threat to her life. As an old, deaf, and penniless woman, she literally has nowhere else to go. The utter disregard for Félicité on Paul's part upsets her sense of home.
What especially upset her was having to abandon her room – so ideal for poor Loulou. (4.47)
When Félicité does imagine having to move out, she doesn't think of herself. Instead, she worries about her dead parrot, Loulou. Home is really about belonging and feeling safe, and while she has no family left, Félicité does see the bird as a connection to a time when she was happy.