Finally I've got some time for a clarification, here.
This picture is a frame still from a short footage about this electric car.
The speaker says that the car was built by the Azienda Elettrica (Electric Agency) for the Governatorato of Rome (AEG), the company that later became the ACEA (the actual water supply company in Rome).
In 1926, AEM ('Azienda Elettrica Municipale di Roma' that was born in 1909) became AEG (Azienda Elettrica del Governatorato di Roma). The Governatorato was founded right in 1926 to rule the Capital. Many other agencies were incorporated under its power. When also the water supply was incorporated into AEG in 1937, it became AGEA (Azienda Governatoriale Elettricità e Acque) few years later known as the ACEA that is still in business.
In those years STFER ('Società delle Tramvie e Ferrovie Elettriche di Roma', that later became STEFER) was under the Governorato too.
In 1941, according to some sources, Bordoni & Ferrero from Rome, built a prototype of an electric 3-wheeler just like that.
Those above are the facts.
My conclusions (but these are just hypotesis) is that the puzzle car is the BF, possibly built by STFER.
Unfortunately I've not been able to find a connection between Bordoni or Ferrero and STFER or AGEA (or AEM/AEG).
I'd like to find any proof about this theory.
