This district was named after a man called Caille, some owner of an estate here, in the 16th century. What is the butte? A kind of "hillock", in fact the continuation of a plateau which surrounded left bank of the Seine, walking around a vast meander of the river Bièvre.
Bièvre? Yes! It used to source in the Yvelines département and enter in Paris by boulevard des Gobelins, then cross the Saint-Marcel and Saint-Victor's suburbs. Tanners and dyers sewage (who worked here) dirtied it, and finally it ran into the Seine. Indeed, in the 19th century, polluting activities such as tannery used to work by Bièvre banks.
We also found on the butte workers and rag dealers, who lived here in awful conditions. Until the World War II, we saw here semi-detached houses with two or three storeys, with those characteristic narrow streets...