Filter for language when using graphQL

I try to use graphQL to get language specific entries from my Craft CMS. I (naively?) tried this:

query {
    entries (section: "newsIntranet", language: "fr") {
        title
        postDate
        expiryDate
        contentText
    }
}

because of this part of doc.
How can I get make sure that I only get entries of a given language when using graphQL from an extrernal system?

query {
    entries (section: "newsIntranet", siteId: "2") {
        title
        postDate
        expiryDate
        contentText
    }
}