Is Napoleon Bonaparte a victim of arsenic poisoning? Are there more such famous cases?

Yes, Napoleon Bonaparte is a victim of arsenic poisoning. In his hair arsenic was found.

Many prominent persons who died by accidental or deliberate arsenic poisoning include:

Napoleon Bonaparte, France, 1769 – 1821
Francesco I de’ Medici, Grand Duke of Tuscany
George III of Great Britain, 1738 – 1820
Charles Francis Hall, USA, 1821 – 1871.
Huo Yuan Jia, China
Clare Boothe Luce, USA, 1903 – 1987.

Emerald Green, a pigment used by impressionist painters contains arsenic. Cezanne, Monet and van Gogh had diabetes, blindness and neurological disorders, respectively. It is said that the contamination originated from Emerald Green.