|Greetings from the Critique Club!
First, I concur with all of the compliments below! In looking at your other photos, it seems that you have a talent for using lines effectively in your photography, and this is no exception. The short lines on the outside walls all point inward, directing our attention to your main subject: the doors. This image also very nicely complies with the challenge of Symmetry. I enjoy the muted tones of the photo, too. I get a peaceful feeling from the shot, almost as if you are saying that City Hall is a peaceful, orderly place. But then there are the strange shapes behind the gothic grating and the door itself: weird trapezoids that add an interesting flare to your image.
If this is just an architectural study, I think you've done well. If you wanted to go further, I would somehow pull more focus to those elements that are most important for your communication. Either way, you may want to think about trying to capture more interesting light for this photo. Perhaps just coming at night or at sunset would give this some lighting punch that would make us want to stop and stare and perhaps even think.
Other technical matters: again, great cropping and point of view, though you may want to think about evening things up a bit and centering the doorway, and it seems your focus could be just a tad off.
In sum, I like this image. It makes me think and I just enjoy looking at it, mostly because of your exceptional use of line. Best of luck in the future!