Language for Google Voice Actions queries

I made a demo app in Android with Kotlin and Google Voices Action to allow me to search in an app after a "Ok Google" (SEARCH_ACTION). It works perfectly well when I said

"Search this thing in my app name"

But doesn't work when I said it in french.

I tried to:

• set up my default research language in french
• delete others recognizable languages
• set up the region in France
• create a second strings.xml for a french version

Is it actually possible to use an other language then english to execute an action in an app from the voice api ? If yes, how ?

Thanks !

I had my answer here.

Where you can use voice search

These actions are available in English in the United States, United Kingdom, Australia, Canada, India, Ireland, Singapore, and South Africa.