Right after David Lawrence Jr says to Marianne 'Manina' Stuart, "We weren't sure that Madame Salvatini would forward it to him.", the street scene out the window behind them skips, revealing a projected film loop starting over again.
When they are touring the ruins of Pompeii, David remarks about the beautiful sunset. But it is obvious from the way the shadows lie, that the sun is still high in the sky.
When David's curious wife Catherine visits Maria Salvatini in Florence, at a very dramatic and emotional moment, during a closeup shot, a fly can be clearly seen crawling down her jacket.