Fairly standard bulge bracket investment banking interview. Technical questions were significantly easier than most banks - focusing on very basic things like "What is a DCF" or "How would you value a company" without digging into the details. Seemed like there was a huge emphasis on "Why Citi". Be prepared to understand why you want the job and be able to express how much you want it. Citi seems to be focused more on people and not preparation (i.e. "fit" questions and not technical questions), so it's significantly easier than most interviews so long as you have a good narrative.