It's a stock that has been clarified. (using egg) I have never done it but my friend did and he was happy with the success. So I guess it's not easy to do.
lots of french fine dine places have consomme.
Le Crocodile Restaurant, Le Gavroche, Lumière..etc.
Since these restaurants change their menu often, may be better to call and ask their menu or do a special request before you book.
It doesn't require using egg to clarify.
You only use egg to clarify if soup is muddy. You can use simmer to avoid muddy most of the time, and you should only use simmer anyways. It's much easier to simmer than using egg.