Transparent i18n rewrite

Hi,

Just switched a project hosted on Firebase hosting to Cloudflare, and i miss an important feature.
Using Firebase, i could serve static html page translated during build time just following the configuration (Mengonfigurasi penulisan ulang internasionalisasi (i18n)  |  Firebase Hosting)
The i18n rewrite is transparent with Accept-Language request header, and no need to have /fr or /es in the url.

Did you know if it is possible with the rich rewrite rules of Cloudflare ? Thanks

My structure is :

index.html (English page)
fr/index.html (French page)