- Why do you want to be at this university/in this department/in this program?
- Do you have any practical experience? What did you do in the lab? What was your project, and what is its scientific purpose?
- What do you do when you come across a problem in your practical work?
- Do you get on well with your supervisor?
- What paper did you find especially exciting within the last 6 months?
- If you had a million euros, what would you use it for?
The best way to prepare for an interview is to gather as much information about the research activities of the group or department as possible (i.e., by reading papers and reviews), and by making sure you know why you would be excited to join this group or department. (Only scientific reasons count.)