Url decoding problem on deployment with IIS and FastCGI on windows server

I realized an app front Angular, back-end Django, deployed on Windows server using IIS and FastCGI. This app serves media files on a certain URL. It works fine locally on dev server. I can access all my files correctly on path "medias/myfilepath".

The problem is in production on IIS. Special characters are encoded in a different way. I think it is FastCGI that does it. I cannot find the encoding rules, and my Django app is not able to decode properly so my requests end up with a 404 error.

Here are some examples of the difference of encoding between local server and production server :

• à | local : %C3%80 | prod : %25C0
• ù | local : %C3%99 | prod : %25D9
• É | local : %C3%89 | prod : %25C9

I can't find any documentation on the subject, I don't have access to configurations on CGI side. I could update decoding on Django side to fit it, but I can't find which one applies ...

Someone would have some ideas on that subject ?

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