Not sure where the best place to discuss is — here or the wiki — but since we already started here…
Remember, I know no French, so I’m reading the English translation. And I apologize if any of this is obvious to anyone who speaks even a lick of French.
Comments about specific sections
Numbers should always be lower-cased and abbreviatedand: nᵒ (There should be a space before the number).
If a release writes out “Symphonie numéro un” or “Symphonie numéro 1” (Google Translate gave me those), is the (proposed) guideline to normalize that to “Symphonie nᵒ 1”? It doesn’t seem like it should; we generally follow the release. Didn’t we recently decide against doing that normalization for volume numbers (vol. 1 vs. volume 1)? [Well, it was 2015, see https://blog.musicbrainz.org/2015/06/02/style-update-2015-06-02/]
Also, do we want to specify spacing? Presumably those should be non-breaking spaces around it.
I think changing all abbreviations to “nᵒ” would be fine. Probably should have an ASCII version too, for people who can’t type ᵒ. Maybe:
If the release abbreviates numéro (number), abbreviate it as “nᵒ” if possible. “no.” is acceptable but not preferred. There should be spaces (non-breaking if possible) before and after the nᵒ/no.
The word “in” should always precede the key name.
The key “ut” should never be used. Instead use “do”.
I presume “in” is a translation mistake. What is the key “ut”? Is there some reason it shouldn’t be used, if that’s what the release does? And as a non-French speaker, is
s/en ut/en do/g safe?
The symbols ♯ or ♭ should never be used. Use instead “dièse” or “bémol”.
Seems to be standardization that we don’t typically do.
English titles in general should follow MusicBrainz’s standard capitalization for French.
I presume that was a copy-and-paste error, and you should have said “French titles in general…”
Parts of titles
We also need to figure out what we’re going to do with mixed-language titles. Classical has tons of them—you can easily get:
Symphony no. 42 in C-sharp major, “Un nom en français”: 1. (tempos in Italian, English, German, …) “First line of lyrics in Latin”.
It’s common to have at least two different languages in a classical title—titles in English, tempos/loudness in Italian. A work title in another language is pretty common, too. And mixing Italian and German or English in the tempos/loudness happens too (though maybe “Adagio” is used so much you don’t consider that Italian anymore).
A title like: “English” « French » «Italian» „German“ or »German« looks more like a ransom note than a title.
It’s also, just as a practical matter, potentially a lot of language guidelines to try to understand and apply to one title.
(A lot of this, of course, would go away if we just followed what’s printed on the release.)
Your examples show spacing around colons, which the other thread let me know is the norm in French typography. With some suggestions on the types of spaces to use. Same with spacing around double chevrons (which I’m not sure that’s always the norm — https://en.wikipedia.org/wiki/Quotation_mark shows it without some places).