Krzysztof Kieslowski was a very precise filmmaker. During the scene in which Dominique has an orgasm, he told Julie Delpy exactly how long she had to moan and when she had to start to moan louder.
An old man trying to throw a bottle into a recycling container is visible at the beginning of the movie. There is also an old woman doing the same thing in "Three Colors: Blue," and in "Three Colors: Red" a similar old woman can be seen again; this time, however, the location is Geneva, Switzerland, it's night, and she receives help from Valentine. Thus, someone finally succeeds in throwing the bottle into the recycling container.
Almost every shot in the movie contains at least one white object.
Julie Delpy shared that Krzysztof Kieslowski would sit under the camera and chain-smoke. Because he always sat under the camera, he was in very close proximity to the actors during close-ups. She said that this was reassuring, as he was solely focused on his actors, but that sometimes it could also be distracting.
Outside the hairdresser salon in Warsaw, where Karol stays and works, you can see the buildings that were featured in Kieslowski's previous film project, Le décalogue (1989).