QueryString Parameters with french characters not decoding

I have a legacy application calling a ASP.NET Core API passing addresses as a querystring parameter. Sometimes these addresses contain French (fr-CA) characters. The application URL encodes the address and we end up with something like:

"123 DE L'%C9CUME" (instead of "123 DE L'ÉCUME")

The problem is inside the controller function I still see it as "123 DE L'%C9CUME" as it's not being decoded.

If I pass the string through 

System.Net.WebUtility.UrlDecode

I'm quite new to .NET Core so wondering if I'm missing a step like adding supported languages to the API?

Any help would be greatly appreciated!