The fascist style is a part of the so-called “Art Déco “, but this style shows in Italy an exceptional aesthetic and innovative quality.
The high quality level of the buildings and of the plastic arts in Italy can be rarely found in other countries.
In the 20’s and 30’s there has been a very interesting attempt to reconcile the roman tradition and the most advanced  modernism.

An intelligent reinterpretation of the tradition
An important characteristic of  Italian “Art Déco” is its harmony with the national traditions and its conformity to the Italian aesthetical manner. Unlike the style of the totalitarian communist and Nazi regimes, which have realized heavy copies, stereotyped, of superhuman size and oriented to a classicism unknown to the national traditions, the Mussolini’s style
extends the realization of the classic without megalomania (it should be emphasized this point, which contradicts a very common statement that history books and tourist guides pass on without  criticism and using - especially for the visible parts - noble and traditional materials (travertine, bricks, marble) without sacrificing (as is the case after 1950) the beautiful to the useful.
A true interest to the  ornamental beauty explains the addition of statues, bas-relieves and mosaics, which often is very well successful.
“The Fascism has been able to amalgamate the most modern trends of that epoch to its taste for the glorious past of the Romanità” (Guide Gallimard -  Roma,  p. 92).

A diversity which reveals the freedom creators and the opening to the modernity

Another feature is the greatest variety of  creations. Contrary to the totalitarian Nazi and Communist states, Italian architects and artists of the twenties and thirties were not forced  to follow strict directives and enjoyed a large freedom in the creation.
The State itself often ordered some buildings to architects who had very different ideas and conceptions (see the Palazzi della Posta in Roma).
It also happened that an architect imposed his ideas to a conservative municipality, which before didn’t agree. So they have been realized works of a wonderful modernism (for example the realizations of Giuseppe Terragni in Como). Many Italian buildings of this period would have been excluded by the Third Reich or by the URSS of Stalin as “degenerated art”! I think, for example, about the architecture (Casa del Fascio in Como, roman buildings of the Dopolavoro in Via Porta Portese), about the sculpture or to the painting (see the works kept in the Museo d’Arte Moderna e Contemporanea   of Trento and Rovereto).
The variety of the trends and the great freedom guaranteed to the creators have saved their works from the uniformity.
The style let also make an evolution to the “historicistics”  works (Stazione Centrale in Milano) up to the almost Germanic severity of the Stazione Ostiense in Roma.
The two major trends are the “functionalist rationalism” (razionalismo funzionalista) and the “neo-roman classicism”
The first one is represented in Roma by the Palazzo della Posta in via Marmorata (Architects: Mario de Renzi and Adalberto Libera, 1935) and by the wonderful buildings of  Dopolavoro in Via di Porta Portese,  which seems a Bauhaus’ work, or by the Palazzo dei Congressi in Roma EUR-E42 (Architect Adalberto Libera, 1938), which is considered a masterpiece of modernism.
sports complex of  Foro Mussolini (also named Foro Italico) (Architect Enrico Del Debbio, 1932) is also a very significant  example among the most  remarkable of rationalist art. It’s very interesting as it’s almost intact . Also the Accademia di Scherma (Architect Luigi Moretti) which is situated in this area is a very interesting and very modern architectural work.
The second trend is represented by buildings, often majestic, with columns or arcs of  travertine as the Colosseo: in Roma EUR-E42 the Palazzo della Civiltà Italiana (Architects: Giovanni Guerrini, Ernesto Bruno La Padula, Mario Romano, under the leadership of Marcello Piacentini, 1938); the Museo della Civiltà Romana in Roma EUR-E42; the lateral fronts of the Stazione Termini in Roma (Architect Angiolo Mazzoni, 1938-1939); the majestic Ponte Flaminio on Tevere river in Roma (Architect Armando Brasini, 1939-1951); the Via della Conciliazione in Roma (Architects Marcello Piacentini and Spaccarelli, 1938-1950).
The Città Universitaria (Architect Marcello Piacentini, 1935) is representative of  both  two  trends.
The San Pietro e Paolo Church in Roma EUR-E42 (Architect Arnaldo Foschini, 1937-1941),  with volumes tightly geometric, abides by a plan in Greek cross dominated by a large cupola of  Renaissance  inspiration, while the cupola decorated with large cases and supported by walls with “
oculi”  is part of the ancient architectonic vocabulary. The statues of this age, especially masculine, are also a  continuation of the ancient tradition, Renaissance and neo-classic. They are an evidence of the level of exceptional quality of the  sculptors of that time in Italia (for example Bianchini or Morescalchi in the Stadio dei Marmi in Roma).

An art and an architecture at the base of the trends and the creations of the post-war period
A large part of the architecture of the post-war period, chiefly rationalist, is born from trends of the fascist architecture. Some of the fascist buildings have been finished after  1945 (for example in Roma: Via della Conciliazione, Flaminio bridge, Stazione Termini, Palazzo del Littorio (nowadays Ministero degli Affari Esteri), Ministero delle Colonie Italiane (nowadays sometime with modifications for example the front face of the Stazione Termini in Roma . 1950).
Also the Architects have continued their work up to the sixties and seventies.