Free download of 2d cutout people for architecture
There are basically two ways to add people to an architectural visualization project, which are by using real 3d models of people, or use some kind of texture applied to a plane, and place it into the scene. I do prefer using the textures because they are based on pictures of real people and give a nice idea of scale to any projects.
If you want to add those textures to a project, the first thing to do is to get some of those textures, and there is a website called Viz-People that is giving away a small collection of 2d cutout people ready to use in architecture for free.
The collection is made of nine different persons showed on the image below, and they are already saved as a png file with a transparent background, making them ready to be used with Blender.