The Man on the Eiffel Tower is a 1949 American color film noir mystery film directed by Burgess Meredith and starring Charles Laughton, Franchot Tone, Meredith, and Robert Hutton. It is based on the 1931 novel La Tête d'un homme (A Man's Head) by Belgian writer Georges Simenon featuring his detective Jules Maigret. The film was co-produced by Tone and Allen as T&A Film Productions and released by RKO Radio Pictures. Wikipedia
Inspector Jules Maigret: (to Johann Radek) By the way - there's one thing I'd like to know. Am I following you, or are you following me?