This was done as a personal experiment. I wanted first of all to develop a distinct architectural style based on my home region in the south of France. I started with some sketches and tried to bring them to a final showcase image.
The second aspect of this experiment was the style and technique. I wanted something slightly stylized and painterly, but without too much texture, This is why I went with the hard round brush.
Finally I had this idea of painting in a way that made lighting flexible after the fact. The idea is to start by painting a diffuse pass first (think albedo+AO pass in 3D) and then adjust the lighting through adjustment layers and flat layers. Only painting over for slight context changes after (mostly the sky).
Overall it was a fun experiment and I plan to explore this world a bit more !