Off rue Champeaux (between Nos 30 and 32), a stroll along tiny ruelle des Chats (Alley of the Cats), as dark and narrow as it was four centuries ago – the upper floors almost touch – is like stepping back into the Middle Ages. The stones along the base of the walls were designed to give pedestrians a place to stand when horses clattered by. See if you can spot the namesake cat in the stonework.