You will be familiar with the long term penetration of the British security services by Soviet agents; Maclean, Burgess, Philby, Blunt etc.
You may be less familiar with the French equivalent. Within the French military and de Gaulle’s government were spies feeding information to Moscow, mainly relating to NATO but also France’s nuclear programme. This spy ring was called Sapphire and went undetected until 1962 when a Soviet defector spilt the beans to the Americans. President Kennedy was so concerned that he wrote a letter to de Gaulle and had it delivered by hand as through official channels it would have been seen by a member of Sapphire.
The news paralysed NATO for about a year and so far as I know no Sapphire spies have been named. But it must have been to some extent in the public domain because American author Leon Uris used Sapphire as the basis for his 1967 novel Topaz. Two years later it was made into a film of the same name by Hitchcock. I re-watched it yesterday.
Topaz was not well received in 1969 for a number of reasons. First, Hitchcock had been making films since 1925 and expectations were perhaps too high for Topaz. He only made two more films, so it is late Hitch. A Cold War spy thriller was not what his audience expected. Much of the film is set in Europe: Copenhagen and Paris, not what was expected. Perhaps most importantly there are no star names in the cast. Audiences had become accustomed to seeing Laurence Olivier, Margaret Lockwood, Michael Redgrave, Joan Fontaine, Cary Grant, Ingrid Bergman, James Stewart, Grace Kelly, Kim Novak, Tippi Hedren and even Sean Connery.
By 1969 Hitchcock preferred to work in a studio so some of the scenes with back projection seem dated today but it has all the classic Hitchcock treatment and music by Maurice Jarre. It is a superb film far above the typical spy thriller. The opening twenty minutes has virtually no dialogue but a lot of suspense. Indeed later there are two scenes in which the protagonists can be seen talking but cannot be heard because they are the other side of glass walls. Later a woman is shot and her dress spreads around her evoking a pool of blood – pure Hitch. Throughout the mundane is elevated. It is every bit as good as N by NW and a pity it’s not better known. By the way the costumes and the cars are a bonus. I loved every minute.