Adventure at the Chateau d'Or (2001), a first person graphical adventure by Karma Labs. Explore Paris and answer questions from the summoned spirit of the lost Duke. As described in the manual:

A modern day princess finds herself caught up in a mysterious adventure when she receives a cryptic letter summoning her to the palace of her deceased uncle, the Duke. Your task is to help the Princess unlock the secret of the Chateau d'Or and claim her inheritance.