My pleasure, I'm also very fond of this genre :)
If you are curious of french animation films, I just remembered "Le roi et l'oiseau". It was my favorite as a kid. And if you liked the city of lost children, it will feel familiar. Sort of the same melancholia.
https://m.imdb.com/video/vi896380441/?playlistId=tt0079820&ref_=tt_ov_vi
I assume it will be hard to find, sadly.
There is this version on archive.org, though, if you can understand french or spanish.
https://archive.org/details/LeRoiEtLOiseau_201709