Uploaded files’ name getting rewritten at Upload

I’m having an issue with files that get uploaded by my website’s users.
I’m using Formidable forms to allow people to submit to events and allow people to add images to their submissions. All is going well in my local environment but online, when people submit files with accents, the accents get escaped on the server side. The issue is that wordpress is keeping the references for these files as unescaped, making me think that this escaping process is not dictated by wordpress but I’m not certain. The result is one where the images can’t be accessed back from the submitted entries even though wordpress knows there’s a file that should be there. Changing the name of the files manually on the server so they match the referenced unescaped name didn’t help either.

I’m not well versed in server lingo but my local environment is this:
Apache/2.4.26 (Win32) OpenSSL/1.0.2l PHP/7.1.7
Version du client de base de données : libmysql – mysqlnd 5.0.12-dev – 20150407 – $Id: b396954eeb2d1d9ed7902b8bae237b287f21ad9e $
Extension PHP : mysqliDocumentation curlDocumentation mbstringDocumentation
Version de PHP : 7.1.7

Whereas the online environment is this:
Microsoft-IIS/7.5
Database client version: libmysql – mysqlnd 5.0.11-dev – 20120503 – $Id: 76b08b24596e12d4553bd41fc93cccd5bac2fe7a $
PHP extension: mysqliDocumentation curlDocumentation mbstringDocumentation
PHP version: 5.6.29

I might give the wrong informations or be in the wrong forum, if so I’m sorry but I’m pretty puzzled about this issue :\
Any help would be appreciated!