Yes, it was a „election poster“ for the 1934 „elections“, and the building is the Palazzo Braschi, where the fascist party had their HQ.

The „SI“ all over the poster is Italian for yes, since the „choice“ you had in this „election“ was this: yes or no… (They were already in power at the time, so that was no real election.)

https://rarehistoricalphotos.com/headquarters-fascist-party-1934/