New Yorkers have been mobbing the Charles Marville exhibition at the Metropolitan Museum of Art (until 4 May). ‘Paris has gotten so expensive,’ I overheard one woman saying to her friend. ‘I used to stay at the Meurice all the time but now it’s $1500 a night!’ Marville was hired as Paris's official photographer in the 1860s to preserve traces of the old city, but also to capture Haussmannisation in action, the demolition and rebuilding necessitated by the new streets, regularised building façades and such monuments as Garnier’s new opera house. Still, to judge from the response of the crowds at the Met, it's the vanished cobblestones and shadowy courtyards, not the rubble and scaffolding, that are the stars of the show.