The exterior shot of the home of the Duchess is actually of Biltmore House in Asheville, North Carolina.
The plot is directly taken from the true story of the "Mad Monk" Grigori Rasputin, and his influence over Tsaritsa Alexandra in pre-Communism Russia.
The palace set is the same one used earlier in the season for The Falcon, Parts 1, 2, and 3. (4.14-16)
This show is another rare instance in which a main character being aided by the team, but not privy to the mission, recognizes the ploy at the end. As Paris leaves the Duchess' room in the disguise of Vautrain, First Minister Picard follows him into the hallway and says, "Thank you, whoever you are". Archbishop Djelvas, in the show "The Heir Apparent, discreetly thanked Cinnamon and added "whoever you are".
Alan Bergmann acted with Leonard Nimoy in the season three "Star Trek" show "The Empath".