File encoding on Django deployed server

I ran into the same issue on my production servers. The important thing is to deploy your django application with the right encoding.

I use gunicorn for deployment and run gunicorn through supervisor. In the supervisor config I defined the encoding:

this is my supervisor config file for the django app:

[program:django_app]
command = /path/to/gunicorn/start/file                 ; Command to start app
user = matyas                                                     ; User to run as
stdout_logfile = /././logs/gunicorn_supervisor.log     ; Where to write log messages
redirect_stderr = true                                            ; Save stderr in the same log
environment=LANG=en_US.UTF-8,LC_ALL=en_US.UTF-8                   ; Set UTF-8 as default encoding

the line

environment=LANG=en_US.UTF-8,LC_ALL=en_US.UTF-8  

is the important declaration. If you don't use supervisor make sure to pass this language argument to the command that starts the django app on your server.

I've contacted tech support and they claimed (...) they use UTF-8 encoding on their servers

This assertion is debatable at best.

On linux systems, file names encoding is not globally set at the filesystem level but depends on the environment - which is usually set per user but can be overridden before executing a command.

IOW, the effective fs encoding for your django app depends on the environment of the process (apache, gunicorn, whatever) that launches the django processes, and the values you find in your own python shell may not be the one seen by django. You did not mention how you're running your django app so it's impossible atm to tell you exactly where to look but at least the above informations should point you in the right direction.

Anyway, is there any way that it's a Django's fault

Complete bullshit.

and it can be fixed with Python/Django hacks

Definitly not. The proper solution is to fix the process environment, period.