The distinctive feature of the French Gothic is the fact that its architects strive to create a perfect Gothic style, greatly emphasizing the above-mentioned characteristic features. French cathedrals (and Gothic is, most often, the architecture of cathedrals) make impression of their complete and astounding verticality, created by the proportions between their horizontal and vertical projections. Moreover, in them the word style makes more sense than, for example, in English Gothic, where almost every building has its own unique features that dont appear at all or only rarely in other examples. The French Gothic, on the contrary, is unified and has more definite set of characteristic features than any other Gothic subtype.
Italian Gothic, being formed in the place where the most famous Classical culture thrived not so long ago, is more eclectic and eager to make its buildings historically-conscious, bringing the elements of classic architecture in them. The most distinctive feature here is the wide-spread usage of polychrome decoration that used different colors in painting both external and internal elements. The black, white, red and other colors interspaced each other; the interior was full of mosaics and frescoes, creating impression that was unique for this branch of Gothic. In fact, although the stained glass, one of the most well-known trademarks of the Gothic architecture, is present here, the windows were smaller than in French churches and they werent considered to be the most important adornment of the interior this honor belonged to frescoes.
Thus, we can see that, although the Gothic was commonly accepted as the main European style of architecture in high and late medieval periods, it wasnt unified. Keeping the same distinctive features whenever it was applied, it still had certain differences respectively to the region, which presents a wide and extremely interesting field for research.