Sharepoint - Can't open document in library with ''é'', ''à'' and other character with accent SharePoint 2016

If you're on a Windows operating system other than Windows 10, you may have a problem with the URL which doesn't translate the àçéèêëïù correct. Instead of using % it may use invalid characters such as à çéèêëïù.

Things to try:

• Open the file in SharePoint directly from Word, and not the browser using Words File > Open command.
• While in classic and not modern mode in SharePoint, navigate to ... > Open with Word.

Reference: Can't open files from Office 365 if name contains accents (Windows 7/IE11)

My colleague found the solution. You need to enable ''Allow high-bit characters'' in your IIS Web Site in the Request Filtering option.