The walls look completely matte to me. They are just a non-metallic, high roughness material. The color variations look like they are painted, so they would be done with a texture in the color channel.
The floor looks a bit more glossy than what you have done (lower roughness), but with a subtle bump that breaks reflections a bit. There also seems to be a spotlight coming from above.
As for the windows, I don’t know exactly how I’ll work them out… I tried to create a glass material and add a point light in the back but the result was a bit weird, the light wouldn’t shine through.