Complex sentence: The chiffonniers (sometimes translated "rag-pickers" in English) were the lowest class of Paris workers; they sifted through refuse on the Paris streets for anything that could be salvaged and numbered about twelve thousand at the end of the Second Empire.
Split into simpler sentences: The chiffonniers (sometimes translated "rag-pickers" in English) were the lowest class of Paris workers; they sifted through refuse on the Paris streets for anything that could be salvaged. They numbered about twelve thousand at the end of the Second Empire.