I can only find this mentioned in the Italian news sites (in Italian) but basically it sounds like it is a super 8 color film that has never been shown to the public before. It is being presented in the Sala d'arme at the Palazzo Vecchio in Piazza Signoria, every day, for free, from from 11 a.m. to 7 p.m. until November 13.
I can't find anything official about it on the Palazzo Vecchio website - many of these Florence museum websites are unfortunately woefully maintained.