IN the grand vestibules of Parisian houses there is often to be found, to the left or the right, a mysterious door, neatly fitted between two mirrors or paintings. I have sometimes been tempted to make a symbol of this door, since to enter it is to pass through Alice's mirror, but in reverse. . . . One leaves the fantasy world of the grande bourgeoisie and enters an evil-smelling passage which winds deviously to the back of the house. Here it reaches that other symbol-in-reverse, the escalier de service, a narrow ill-lit staircase that spirals upward for a dizzying seven or so floors. It was up here that the housemaid would scuttle to reach her tiny chambre de bonne, while her mistress sailed up the main staircase, fluttering fine linen. On their arrival in Paris it is with this door, this staircase and this humble chamber that most impecunious youths became intimately acquainted. Thus has been the case for over a century; no sooner had the housemaids begun to disappear from their rooms and from history than countless young Decadents - whether in flight from paternal wrath, from the provinces or abroad - started to move in. Today, for example, the upper storeys of the noble rue de Rivoli are infested with students - many of them temporary teaching assistants from abroad - and unless they 'live in' with the family below, the same iron rule applies throughout: 'Where the carpet starts, you halt!'

Unless one ...