AGilbertDev Québécois French copy
All French copy is Québécois, never français de France. Follow my own usage. Write "dans mon temps libre" rather than "sur mon temps libre", treat "un stack" and "mon stack" as masculine, and use "outils" rather than "outillage". Colloquial Québécois fits my voice, for example "le fun à faire". Write what I would actually say, and never adjust toward France French.
Every visible French string must be researched and correct, never guessed. When a term has an established Québec usage in the domain, use that one.
Punctuation
French punctuation uses a real no-break space before ? ! : ;, and that character is U+00A0. Not U+202F, the narrow no-break space, and not a plain space. Write it into the locale file as the literal character rather than as an escape. A JSON renders correctly and then reads as a plain space to every grep, diff, and reviewer, which is how one gets deleted by accident.
Checking it
Check with grep -P '\x{00A0}' and never with grep -P '\xc2\xa0'. The byte-pair form looks right and silently reports nothing when grep is a wrapper around ugrep, which reads those escapes as two codepoints in a UTF-8 locale. Prove whichever form you use against a probe file holding a known U+00A0 before trusting its silence. Prefer a committed test asserting the rule over a command run by hand.
Dates
Intl.DateTimeFormat produces no French ordinal, so "1 août" comes out where French wants "1er août". Use formatToParts with Intl.PluralRules of type ordinal. For fr-CA it returns one for 1 and other for everything else, which is exactly the French rule.