Even though about half the series takes place in Paris, this is the only episode to feature the Eiffel Tower as an actual set instead of just a backdrop scene.
When looking at the Chronicle DVD, there is a picture of an immortal from 1818. In 1814, Joseph Niepce made the first photographic image using an early device for projecting real-life imagery called a camera obscura. However, the image required eight hours of light exposure and later faded. It is highly unlikely there would be a photograph, let alone in color, of a man from this time period.