I saw an English language film (spoiler, it was >!*Poor Things*!<) where events partly take place in Portugal and France, including locals speaking Portuguese and French – lines that were not subtitled, obviously meant to go over the head of the characters (and, presumably, the parts of the audience that doesn’t happen to understand Portuguese and/or French).
This made me think about the challenges of dubbing a film like that. According to [the Wikipedia article on dubbing](https://en.wikipedia.org/wiki/Dubbing#General_films_and_programming), “[i]n the French-, Italian-, Spanish-, German-, Russian-, Polish-, Czech-, Slovak- and Hungarian-speaking markets of Europe, almost all foreign films and television shows are dubbed (with the main exception being the majority of theatrical releases of adult-audience movies in the Czech Republic and Slovakia). (..) In Spain, Italy, Germany and Austria, even in the largest cities, there are few cinemas that screen original versions with subtitles, or without any translation”).
Leaving aside that exact list of countries and how accurate it is, and even this film in particular, how is a situation like the one I described handled in dubbing? Say, an American film where parts of the dialogue is in French, maybe even takes place in France, and is not subtitled or even understood by the characters. How would that be dubbed in French?