Was contacted by a recruiter - 3-round process.
The first round was motivational questions and a test of understanding of the firm (conducted by a recruiter).
The second round was similar, but with more competency and behavioural-style questions.
The third round was a repeat of the second round with more senior recruitment personnel. Nothing is too complicated; however, the interviewers tend to dig very deep and will often ask 3-4 follow-up questions for each question.
They also look for candidates who behave in a very interactive way, as if the interview were between two colleagues of the same rank, rather than a traditional interview.
There is a 10-15-minute role-play towards the end in which you simulate a cold-call scenario. I would say this is the most challenging part of the process.