The interviewer asked standard interview questions like your weaknesses, failures, and examples where you worked in a team. They also asked why you want to work for IMC trading and also about any knowledge you have about trading (in general - not just the software). Note this was just the behavioural part and not the final technical and behavioural interview.

for online assessment, there was a question about calculating info from an order book. helps if you know how one works beforehand. only one question and coding preferred in C++ or java.