Applying the same economy used in César's other films — one shot which uses the duration of an entire 16mm film reel — Porto 1975 is a tracking shot that unfolds at the social housing complex Cooperativa das Águas Férreas da Bouça, designed by Álvaro Siza Vieira as an integral part of the Ambulatory Service of Social Support (SAAL, 1972–76). The work's construction was initiated in 1975, but only completed in 2006. At some point in the film, the voice of the architect Alexandre Alves Costa, coming from an obsolete answering machine, conducts the deambulatory path to the interior of the building, and recounts the troubled times surrounding the construction of these dwellings backwards to 1975, the tumultuous post-revolutionary Portugal.