copy readable UTF-8 url from firefox
URL : about:config
search
network.standard-url.escape-utf8
change
network.standard-url.escape-utf8=true =>
network.standard-url.escape-utf8=false
OK !
Bonus gift, you can accelerate the cache and give some more years of life to your SSD by moving the firefox cache to /tmp (mounted in tmpfs) by right clicking and adding this string:
browser.cache.disk.parent_directory = /tmp