For non-French speakers this could be the most overwhelming element. When my son started his first year he really didn’t speak much French, therefore the language was a concern for us. Geneva has a large expat community, therefore we were not the first in this situation and the school systems are totally prepared for this challenge.
In the book, Margaret discusses how the school system deals with this limitation at all ages and even for children transiting from private to public school. The education system has seen it all, she says, so they have the proper systems in place.
What we found particularly helpful, in addition to the author’s explanations, are interviews or opinions from children and adults to provide a good idea of what to expect.