If you are using iOS >= 12 and set device language and region to France (fr_FR) Device settings IMG and fetch current locale from the code:
[NSLocale currentLocale]
or
[[NSLocale autoupdatingCurrentLocale] localeIdentifier]
result will be en_FR.
Keep in mind that app has localization for France Localizable.strings IMG and info.plist contains
<key>CFBundleLocalizations</key>
<array>
<string>en</string>
<string>fr</string>
<string>it</string>
<string>de</string>
</array>
Why is this happening? Did I miss something? Same approach is working on iOS < 12.