The lyrics describe a young, well-meaning but naïve shepherdess, Margot, who finds a lost kitten and adopts it.
This attracts a lot of male onlookers and brings all life in the village to a standstill.
[1] When Brassens died in 1981, French cartoonist Jean-Marc Reiser made a graphic homage, in which a man sits in a train talking about his disgust with Brassens' filthy lyrics.
While he talks a young woman sitting in front of him breastfeeds her cat in the manner of Brave Margot.
This sight touches him, as he recognizes the image from the song, causing him to reconsider his opinion about Brassens' music.