Oh I wasnt talking about TTL specifically, just the broad idea of Brazil(usually its Imperial version under the Braganzas) becoming a superpower equalling architecture staying the same portuguese baroque of the 19th Century
I really like the Portuguese baroque style of the 19th Century, but I agree with your statement. The most I see happening is this becoming the mandatory style of public buildings. Then the style would become the standard of government (just like Greco-Roman is for the USA).
Would pursue practical simplistic designs not too far off from what the americans did IOTL
Perhaps, it is difficult to say this because it is a style that focuses on practicality above all and is something very American.Tthe European countries preferred a mix or a big focus on style before entering the america sphere. The nation ( french colony) will not have the same pressure as the US in relation to the industry, which reduces the rush for mega practical buildings, so I guess it would be a mix of both.
The advantage of the nation are others and I don't think it's possible for it to have the same industrial strength as the usa. Depending on how it goes in the future, the colony could literally become a domain of France instead of becoming independent (which would be something very unique, with France being forced by the colony or by its own decision giving autonomy to the colony. Being in the long term +- 20 century being surpassed by the colony).
As for the French Brazil of this story, I expect something like the french "Art Deco" to be the style that defines its Modern incarnation if it prospers, like Paris's contemporanean architecture
If France has the same traumas as OTL, I think a contemporary style of architecture is likely. If I don't think something in this style is probably not going to become popular. Colonies tend to have extremes of the positives and negatives of metropolis culture. So for example the French colony can be very aristocratic and jingoistic while being a great patron of arts and science. The colony might have for example a weirder version of the three estates (perhaps even a fourth, being the slaves). TTL bandeirants (pèlerins) can become a warrior class like the Cossacks. In otl Cossacks guarded the frontiers of the Empire and in return were granted land privileges. Cossacks were also used to repress uprisings against the Russian state. OTL bandeirantes carried out the expansion of the colony (but privately with little monetary support from the metropolis) and when paid they dealt with rebellions and enemies of the Portuguese crown such as the quilombos (mini African kingdoms within Brazil, made by runaway slaves), Spaniards, tribes of indigenous peoples, etc. With the French state being the neurotic creature always wanting centralization, bandeirants (pélerins) stand a high chance they have some form of contract with the state (perhaps they create companies that are registered with the crown or are bankrolled by local aristocrats). The colony can turn and have a lot of strange things.