I see this thread is a few months old but in seeking information for myself on drones in Piedmont Park I found two items impacting flight in downtown Atlanta:
1. From the Parks and Recreation Regulations and Guidelines - Sec. 110-72. Model airplane flying
No person shall engage in model airplane flying in any public park, except at or upon places designated therefore; provided, however, that no person shall operate more than a 35 cc piston displacement motor.
2. The Georgia Building Authority passed a resolution banning the use of drones in our around the statehouse building and within 5 miles of the Capitol Hill Heliport (which sits across the street from the statehouse. (From an AJC News article dated June 29, 2015)