Greetings Deep Magic,
Though rahul has replied to your query, I thought it might help if I share my recent interview experience.
1) I had to travelled to a different state in US for my interview. While scheduling the interview, I requested both the interviewers to adjust me on an agreed date. They were quite flexible even though very busy.
2) You need to prepare a presentation on any topic...I mean any topic that you are comfortable with. You should be able to answer any questions that the interviewer might have on the presentation. If you don't know the answer, better smile and say that you don't know and need to check. Bear in mind, they are not going to drill you on the topic. They just want to see your level of comfort and confidence while delivering the presentation.
3) Be prepared to answer questions like:
Why MBA?
Why now?
Why HEC?
Why in France?
What will you bring to the school?
What if not HEC?
What other school r you looking at?
Questions from your essays and CV ?
And finally, do have some meaningful questions for the interviewer to answer.
Play it cool man. I'm sure you will do great in your interview. If you can score 750 in GMAT...this is nothing
Best of Luck!!
DK