You might be thinking of Graham Robb's 'The Discovery of France'. He's written biographies of Hugo, Balzac, Baudelaire and Rimbaud, so would presumably know the French 19th century well, but I'd still be a little suspicious of the book, if only because in his new work, "Parisians' he apparently has some very unkind things to say about the communards - although I suppose you could argue that he went one better than most mainstream historians in that he at least mentioned them. David Bell's review, admittedly published in the New Republic, seems a fairly convincing critique of the 'discovery' book:
http://www.powells.com/review/2008_02_07.html