Yes and no. When referring to the cut, yes, the chateaubriand is essentially filet mignon roast. Chateaubriand is the trimmed tenderloin served in a large cut as a roast. Filet mignon are steaks cut from the tenderloin, but they can also be cut from the tips of the whole cut and not just the center. See our full guide on how to trim a whole tenderloin for more info on what makes these the same, and different. They are both tender and lean and are best paired with rich sauces for the best results.