Les Rosenbergs ne doivent pas mourir

[LL1]

I'm searching for a French tv production called "les Rosenbergs ne doivent pas mourir", produced in the mid-1970s: https://www.imdb.com/title/tt0335385/  I've contacted the French production company which bought the original company which produced the film, French film archives, as well as university archives on the Rosenbergs, but none has heard of or has a copy of this production.   It is not available on Amazon (although the book, upon which the production is based, is available).   Any suggestions of where else I can find this production?  I am looking for a copy for personal reasons only, and not to show in a commercial or public setting.