Filet mignon by John Spottiswood.

These are cut from the tenderloin, and they're the most tender steaks you can buy, though not the most flavorful. American butchers usually call all tenderloin steaks filets mignons, but the French reserve the name for just the cuts at the small end of the tenderloin, which is the best part. As they move away from the filet mignon, the French call their cuts tournedos, filet steak, châteaubriand, and bifteck. American butchers confuse matters even more by sometimes calling top sirloin steaks châteaubriands. Don't marinate these steaks and don't cook them beyond medium rare.