After reading this article in the New York Times, I'm glad there were no scenes in the book (I haven't read the script) set near Campo de Fiori or Piazza Farnese.
Regarding the Church saying no to the filmmakers, I thought the filmmakers had balls to ask to shoot inside churches. Did they not read the book? Why would the Catholic church say yes?
Anyway I hope this movie is better than the Da Vinci Code. The Da Vinci Code made a ton of money but movie was terrible. I couldn't finish it.