You will not have a similar situation in Geneva because the environment is very international. Most private schools offer bilingual (usually French and English) programmes and in addition other possibilities to study foreign languages.
German is the first foreign language children learn in public schools. If you decide on the Swiss public system, most children her age will not speak a lot of German so she will probably be the best in her class. Admittedly, she will have to learn French.
If you would like an easier transition for her, you can check the German school
http://www.dsgenf.ch/index.php?id=63&L=0 I have German colleagues whose children go there and they are very happy.
The general reputation of public schools is that they are not very good at foreign language teaching or at least that private schools are much better. It all depends on the school and the teachers and eventually what you want.
My children started school this year -- in a private French school which has 3 periods of English from the start (they are in the nursery school). Even though I was sceptical in the beginning, I have become really impressed with what they have learned so far. I can see that they will soon have very good English skills -- this will be their third language and we do not speak English at home at all.