Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Sympathetic with a Dash of Tongue-in-Cheek Irony
For the most part, the narrator is pretty kind to Félicité—even if she does hang around with a stuffed bird and thinks that you can get from Cuba to France by land. It's subtle, but the narrator gives us her background so that we'll know why she is so ignorant. For example, in the case of geography, "the only book learning she had ever received" comes from Paul, who once explained an illustrated geography book to her.
On the other hand, there are some moments where it would seem that the narrator might think that Félicité's ways are just kind of funny. It's pretty subtle again, but when she dies, her final vision is presented in such a serious, climactic way that the final words almost seem like a punch line:
[A]nd as she breathed her last, she seemed to see, hovering above her head as the heavens opened, a giant parrot. (5.13)
The joke is only at the end, but it's there.