- You must know something about Italian politics in the last 10-20 years. - You must know what Partito Democratico (or PD in brief) is: it is a political party born out of the transformation of the Italian communist party (PCI) in the 1990s, it is now one of the main political parties in Italy, and it is a left-wing party. - Many former voters of the PCI were unhappy at the time with the transformation of their party into PD as they felt it moved too much toward conservative policymaking. While the party changed, ideology did not as much, and still many people nowadays declare to be Communists or follow ideas that closely resemble the kind of Socialism debated in the 1960s and 1970s. - Italy's economy is suffering from structural deficiencies, corruption, and backwardness. Consequently, people today feel poorer and many struggle to keep up with economic change and rising costs.
Now, assuming that you as a viewer have these points clear in mind, the movie tries to represent the contrast between people from the streets, and the PD party. People from the streets are unhappy, poor, and they would like to be represented by a political party that fights for far-left policies. For some reason not explained in the movie, these same people do not vote for a different, more leftist party but instead continue to recognize the PD as the one-and-only party representing (that MUST represent) their political views. The solution to this impasse is represented in the movie by a sort of revolution where "the people from the streets" overrun the local site of the PD.
The movie is boring, no memorable gag or funny situation is ever seen, save perhaps for the representation of a bit over-the-line characters who someone might find mildly entertaining. The satirical content is unsatisfactory and requires the viewer a good dose of leftist ideology himself to enter into resonance with the situations. Acting and direction are bad. Music sometimes seems to be unrelated to the video and is anyway itself uninteresting. The director chose to use saturated colors: at the beginning this looks like a smart idea to represent the suffucating heat of Summer (which maybe hints, metaphorically, to social heat rising among the people), but after 20 minutes or so it becomes just annoying.
In summary, try to avoid this movie, there are many better things to do in life. People suffering from that disease called ideology are probably unfit to make jokes about themselves, and this observation fully applies to the director and author of Arance e martello.