It happened at the Louis Redding City-County Building at 800 French Street around 9:00 a.m.
Firefighters were called to the building for a report of smoke on the fifth floor and a light haze on several other floors.
Fire crews searched the building and said the smoke extended all the way to the ninth floor. They were able to determine that the smoke was caused by a faulty air-handler unit.
The air-handler unit was taken offline and the incident was declared under control at 10:04 a.m.
There were no injuries and the building was reopened for business.
