I am not thinking of mere forms of politeness, such as saying "please" and "thank you" : formal manners are most fully developed among barbarians, and diminish with every advance in culture.
The culture has changed: its hosts and hostesses, known as Gentils Organisateurs, now have to address customers with the formal vous rather than tu in public.
The new National Museum of African American History and Culture (NMAAHC) is a rare example of permanent, formal architecture with many of the traits of protest construction.