In Firenze, most of our properties are in ancient buildings called "Palazzo". Some are relatively small, 4/6 properties whereas others can be bigger buildings but all with residents and offices.
All the buildings have it’s own property Manager in charge of the building maintenance and often STRICT rules against noise and safety!  Please respect our Italian style. 
Renting an apartment in Firenze it will typically be given a minimum of two keys: one for the “portone” (or main door to the building” that you never Lock and one for the apartment. 
Upon entering the building, you find a foyer with stairs ( luckily a lift ). Did you check the floor of your apartment? Remember in Italy the ground floor is what in the US is called the first floor. Each floor is made by two flies of stairs of at least 15 steps! Make your counts when you book and travel light!
On the wall at the foyer spot a little, generally white, rocker type switch that can control either the lights or open the main door (to get out).
Once you get to the target floor and found your door, maybe an anonymous solid-looking windowless brown door, insert and turn the key in the opposite direction of the wall (or if it’s a double door opposite the fixed door)  until it stops or makes a click and push gently the door.
When you go out NEVER forget the key in the lock (inside the door). To reopen a locksmith will be necessary and €150. Not funny at all!! 
But Just don’t forget to shut all the doors behind you! 
Not all of Italy’s apartment lockers are complex but some can cause problems due to heat/cold that can inflate the wood and make it tricky to open our doors.
If you face some difficulties just send us a message and we will report to the PM. 

Happy entering and exiting!

“Expect problems, and tackle them creatively“ (Diana P.)