BBC Four: At the time of his death in 1995, Malle was in pre-production on a biopic of Marlene Dietrich. What can you tell us about this project?
Philip French: There were several things about Dietrich that fascinated him, one of which was the way in which she left for America just before the rise of the Nazis and had the courage to come out against the Nazis and throw herself into the war effort, going in uniform to entertain American troops. He didn't judge people but Malle had a moral concern with the behaviour of the French people during the Occupation, which he experienced from the age of eight or nine and dealt with in Lacombe, Lucien.

Malle was also fascinated by the way that Dietrich had been able to retain her German identity rather than becoming American... This is something that interested him. He had been, since childhood, very interested in American movies, music and literature and made a decision to go to America and try to make American films that perhaps expressed his French sensibility. But they were not to be the films of a visiting Frenchman. I think one sees that in his films - that he was immersed in America. So he had tremendous regard just for her individuality and he was also a great admirer of the movies of Von Sternberg.

BBC Four: Which other projects did Malle have in the pipeline in the mid-90s?
PF: There were several writers that he was working with. He was working on a script with John Guare, who wrote Atlantic City, and he was also working on and off with Terrence Malick, who spent several summers at Malle's house in the country.

BBC Four: The documentary is entitled The Passions of Louis Malle. Having known Malle for a number of years, and written at length on his work, what do you believe he was most passionate about?
PF: Well there was one thing off-screen that he was passionate about and that was women. He also had passions for jazz, cycling and literature. He loved travelling and recording his travels and a number of these journeys are the subject of documentaries. He went out briefly to Indo-China at the time of the war, he visited Vietnam and he spent some time touring Algeria, which was quite influential on his thinking about society. He made a short film in Bangkok, there was this long period in India and then the documentaries that he made in the States.

But the big thing I suppose - in which he was able to draw together the love of women, jazz and travelling - was film itself. He begins the second of his feature-length American documentaries - a film called God's Country (1986), which was almost entirely shot in Minnesota - saying, wonderfully, "To be out on the road again, shooting a film and meeting people." So I think that was also it - he had an endless fascination for people but then he had an endless interest in so many things. There was no subject that bored him.