La Samaritaine is a department store built as one great room. Iron balconies climb four floors round a central well, painted in green and gold, with a long enamelled frieze of peacocks running along them and a glass roof over the top. Stand on the ground floor and you can see every department at once, which was exactly the point. A new front on the street behind is a wall of glass folded into vertical ripples, and it was not designed to match the buildings beside it.
Two market traders opened a shop on this corner in 1870 and spent the next thirty-five years buying the block around it, one building at a time. In 1905 they handed the whole site to the architect Frantz Jourdain. Instead of dividing it into rooms he threw an iron frame across the lot, roofed the middle in glass and left every floor open to the well. It has been a listed monument since 1990, which is why the room you stand in is Jourdain's own, down to the paint on the ironwork.