They tend to examine the logical thinkers that can communicate clearly and concisely, and some problem-solving exercises intended to explore how you gather and apply new information, very different from other tech companies' interviews.
J'ai postulé en ligne. J'ai passé un entretien chez Jane Street
Entretien
Very nice and friendly interviewers. They called me on my phone and took time to guide me when I was stuck. No question concerning my background, my CV or my motivation.
Initial application and online assessment. Had a first round behavioral interview where they asked me about myself, my experiences, and a couple of brain teasers. The interviewer was very nice.
J'ai passé un entretien chez Jane Street (Londres, Angleterre)
Entretien
Phone interviews (at least 3) - questions were of mixed difficulty (some pretty hard) but the interviewers were friendly and they gave helpful hints. Kind of fun - review probability and game-type questions.