Just to inform you, even you choice the Voltaire or Bonaparte school, I just know the French nursery named Perles d'avenir, it's new one, but incredible fantastic !
I have my daughter there (26 months old) and she and I really love it ! If you need more details check their website : www.perlesdavenirqatar.com.

About Voltaire, i know that they will open a second school, and they are a nice french school.
If you are French you will have a big discount on it. I know that they provide a qualified french education and add with that the history/geography and arabic language to be adapted to the qatar.
I think that an interesting addition !

Good luck to your choice.