In his busy life Balzac wrote many love letters, and in The Human Comedy he portrayed many female beauties, but he certainly never imagined or met a creature as 'sparkling and proud' as his beloved city. The ever-new Paris to which he addresses his declaration of love consists of an accumulation of details - names, landmarks, streams, gates - a city with countless meticulously drawn figures: legal clerks, grisettes, journalists, concierges, usurers, salesmen, speculators. Balzac gathered the elements of this Paris by sauntering through it. 'To saunter is a science,' he writes, 'it is the gastronomy of the eye. To take a walk is to vegetate; to saunter is to live.'

This book follows in Balzac's footsteps, crossing the city in his big boots, running between his printers, publishers, coffee merchants, mistresses and friends, stopping for a moment, struck by a detail that his photographic memory faithfully fixed. 'There are memories for me at every doorway, thoughts at each lamppost. There is no facade constructed, no building pulled down, whose birth or death I have not spied on. I partake in the immense movement of this world as if its soul was mine.'