I applied online. I interviewed at Citi (London, England)
Interview
First stage was an online screening test in quantitative reasoning. Then on to a phone interview stage with an HR person - all questions were of the fit and behavioural kind, so be prepared with your examples. The last stage was an assessment centre which was took whole day: 3 1-to-1 interviews, a case interview, group discussion, presentation and a role playing interview.
Interview questions [1]
Question 1
All questions were rather standard and focused on the fit, very few technical questions: matlab, past projects at university etc.