this might be related to a local encoding in the server or client applications. On my system I cannot reproduce that.
Can you access the API in your browser and see if you also see the garbled content?
Thank you for the reply ! Yes by accessing to api via the browser all the accent are well displayed !
I have the problem when I ask via my powershell script. I use the Invoke-RestMethod to hit api from my powershell script. I searched on google and it looks like it is a known problem. I dit no find any solution yet.