Internationalization does not seem to work with site:run

I've tried performing site:run with the internationalized site created by the site archetype (not the simple one), and I cannot get it to render the french pages, no matter what I do. The /fr/* URLs are missing, and when I switch my local in FF to fr-FR, still no change; it's still in English.

I suspect that site:run isn't looking at the src/site/fr/** directory, and/or it's not detecting the locale of the browser.