Well, you have to finish your undergraduate. First of all, do well in your courses for the remaining time in France.
Start doing readings, you don't need a professor for this. If you are interested in AI - pick up the AIMA book. Go through conference proceedings - say IJCAI - it has a section on robotics (http://ijcai-09.org/technical_program.html).
Read as much as you can, don't just flip superficially through the material, but also don't spend huge amounts of time if you don't get something. Think. Ask yourself questions. Have a notebook and write down notes - the model, theorems, main ideas of the proofs, and anything else that comes to your mind, even if it seems trivial at the moment. The act of writing will force you to think about the material and will clarify your thought processes (I find this true in general, not just when reading papers). Here is some nice advice on how to read a research paper: http://blizzard.cs.uwaterloo.ca/keshav/ ... eading.pdf.
Finally, don't get too stuck on MIT or CMU. There is an element of randomness that you can't control in the admissions process, and it is much easier to get into these schools if you have letters of reference from professors known by the admissions committee. It is not fair, but that's how it is. Even if you don't get in for PhD, you may do a postdoc there later.
Rather, set your goal to get one or two papers in top conferences before applying. This site has CS conference rankings: http://www.cs-conference-ranking.org. Even if you do all the work on your own, you will likely need the help of a prof when editing the paper for submission.