Applied at end of December, offer by early February. (1) Initial standard application and online tests. (2) HR telephone screening about motivation to intern, ability to work 5 days in-office etc. (3) First round: two back-to-back interviews focused on CV, experience and extracurriculars. (4) Final round: with directors, presentation followed by a Q&A and final interview. Presentation topics were provided by HR, or you could pick your own; interview portion was similar to first round. Interviews were very conversational, friendly and focused on gauging skills and culture fit (but other departments may ask technicals). Average difficulty for an internship.