Very, very nice!
If you plan/mind to share it for the official pakset, some details should be changed (mostly, the floor tiles should be standard textured).
Also, City Halls should be designed for at least 3-4 city sizes.
E.g.
size 1: only main building and 2 floors lower
size 2: just the main building
size 3: add one side wing
size 4: add the second side wing
Additionally (but easy if it comes from blender) it's preferable for it to have all 4 rotations.