> I'm sorry but that's absolutely wrong. You don't become an Architecte en chef by promotion, it's a competitive exam
No, Architecte et urbaniste de l'État is an exam (like everything regarding the civil service in France). Architecte en chef very much is a promotion. It's the grade following Architecte de l'État and preceding Architecte générale.
> Most architects with this title have businesses of their own
No, they are all civil servants and work for a minister.
> navigating the civil service
Yes, being promoted is very much about getting old and navigating the civil service. Architecte et urbaniste de l'État very much is a managing position with all it implies when you are working for the state.