Firefighter (NPC)
The Fire Department will respond to a fire alarm when there is a fire, but if there is no alarm in the room where the fire is, it is best to phone them up quickly. If they are called when there is no fire, there is §500 fine, and in The Sims 2, the Sim who called will get a negative memory of being fined. The Fire Department will come in a fire engine (The Sims 2 or later) and the firefighter will carry a large fire extinguisher and a tank on his/her back. Once they start to extinguish the fire, build and buy mode will be available. In The Sims 2, firefighter outfits are available through the BoolProp testingcheatsenabled cheat. In The Sims, the firefighter is male. In later games, the firefighter may be male or female, but will usually be male.
In the trailer for The Sims 3: Ambitions, it shows Firefighters scrambling in what seems to be the fire department, showing firefighters getting changed, sliding down poles and it also shows a fire-truck. As Firefighter is a new career in Ambitions, this is presumably the workplace for the career, but it could simply have been specially made for the trailer.