Leonard Nimoy stated that George Sanders sat quietly by himself and did not interact with anyone off camera. He only appeared on film four more times, and committed suicide in 1972 at age 65 by ingesting five bottles of a barbiturate. He left a note naming boredom as the main reason for his suicide.
This was the final appearance for both Leonard Nimoy and Lesley Ann Warren as Paris and Dana respectively.
The "secret radar base" is actually a NIKE missile site near Brea California (since decommissioned). The reason the hills are shown as burned off was because there was a wildfire in the area shortly before the episode was filmed.
After the opening credits, the establishing shot titled "The Mediterranean" is a view of Cannes, France looking roughly westward along Boulevard de la Croisette. The neon sign for the Carlton hotel is visible.
This is the last MI episode Lesley Ann Warren appeared in and the much talked-about scene where she is bra-less in the see-through white top starts at the 24:30 mark when she is exiting Leonard Nimoy's hotel room. At the time it was a short-lived fad for women to go bra-less and wear see-through blouses.