Using LIKE to search case insensitive over language specific characters (PostgreSQL)
unaccent

The traditional, non-PG 10 method of this is to the extension unaccent.

CREATE EXTENSION unaccent;
SELECT 'a' = lower(unaccent('Å'));


You jam this into a TEXT SEARCH CONFIGURATION

WITH unaccent, french_stem;


And then magically all of your fts stuff works as English speakers desire.