I applied through university. I interviewed at Lazard (Minneapolis, MN)
Interview
Applied through campus recruiting. The interview consisted of back to back interviews with two different people (30 min each). The first was simple resume and general employment questions. The second was much more challenging and also included specific, financial knowledge questions. In true investment banker fashion, the interviewer looked as if the life had been sucked out of him. The interviewer does his best to "psyche you out" (looking bored, fidgeting with things, looking at his laptop, etc.). Either that, or he just really didn't want to be there.
test both peronality and some math -> hire view usually 5 qeustions, always includes why lazard why investment banking -> interview might be 3 interviews, 2 behavioral and one technical, maybe prepare some case studies, and market sizing
I applied online. I interviewed at Lazard (London, England)
Interview
Basic Behavioural interview questions. Asked about past experiences in life, times you showed leadership and adapted to different situations. Complementary with an online assessment, which all together takes in total about one hour.
First round phone interview with an AD was mostly technical. Just a quick "Walk me through your resume" type question and then the rest were either accounting, paper LBO, or brain teaser. On the more difficult side, but not unreasonable.