Nelson Riddle's instrumental recording of "Lisbon Antiga" (an ancient Portuguese melody) was already on the hit charts before this film was made. Republic publicity sent out a story that "Director/Producer Ray Milland took a recording of the music with him and had a Portuguese orchestra adapt it for a sequence in the picture".
"Lisbon" was originally intended to be filmed by Paramount Pictures for star Joan Crawford in 1953. Script difficulties prevented the movie from being produced.
Strange choice of wines by Captain Evans! When he meets Mrs. Merrill in a tavern of Alfama, he suggests her to try "a Madeira, or something!" instead of water. Madeira is a strong aperitif, too dry for most tastes, good with entries such as paté, cheese or sweet desserts - which was not the case, while he had dozens of softer Moscatel type wines from the Douro to Arrábida, to chose from. Also, Captain Evans has dinner with Maria Madalena, and accepts the suggestion of Mateus Rosé for the red wine; Mateus Rosé being a famous export label for the American market (then, and in the 21st century) but not for a Portuguese. Someone like Captain Evans, who has a long tradition of visiting Portuguese ports, would have known better.
Probably to get some extra funding for the film, Milland squeezed some publicity into "Lisbon", such as a very conspicuous Lockheed Constellation airliner of the old TAP (Transportes Aéreos Portugueses, nowadays TAP Air Portugal), as well as the usual Mateus wine bottle, which does not look quite rosé in this movie. (If one goes to a fancy restaurant you order more sophisticated Portuguese wines). The views of Lisbon are probably adjusted to the modern image that dictator Oliveira Salazar wanted to show the world. The splendors of the capital city of Portugal are probably better shown in other films.
The house of Aristides Mavros - interiors and two garden scenes - was the property of banker Ricardo Ribeiro do Espírito Santo e Silva (12-11-1900 - 02-03-1955), referred by American source as «the mansion of banker Esperito Santo». [sic] Since he had two mansions in the same neighborhood, this was the smaller of the two, the so-called «pink house», at Estrada do Guincho, later renamed Avenida Rei Humberto II de Itália.