It is an ancient tradition of making animals talk and giving them a human character to derive a moral from their stories. La Fontaine presents fables with which he has infused a French character.
These fables are perhaps the first poems that I read in my childhood. But, in my youth, I read the entire collection, and it has not lost its grandeur. Fun work for children (sorry, "Master" Rousseau) and an absolute delight for adults.
The fables are a fantastic work that mixes the comic and the serious, the most diverse subjects, with a flexible and easy-to-learn verse (some verses are true proverbs). I noticed that this work is better when you read it simultaneously with the other results of this century: Molière, Racine, La Bruyère, Boileau, Bossuet or La Rochefoucauld. We take full advantage of it!
Do not hesitate to read the entire collection and not just read the few famous fables because they have surprises!