As for T181927, could you add French namespace translations.
Here is the code to add in Wikibase.i18n.namespaces.php
$namespaceNames['fr'] = [ WB_NS_ITEM => 'Élément', WB_NS_ITEM_TALK => 'Discussion élément', WB_NS_PROPERTY => 'Propriété', WB_NS_PROPERTY_TALK => 'Discussion propriété', WB_NS_QUERY => 'Requête', WB_NS_QUERY_TALK => 'Discussion requête', ];
And for "Lexeme", I am not sure the file is WikibaseLexeme.i18n.alias.php. Anyway, the French translation of "Lexeme" is "Lexème".
Thanks in advance.