What help is the school giving your daughter?
Here, when we arrived, my daughter, aged 12, spoke no French. Three of her four weekly English lessons for the first term were replaced with a 1:1 with a French teacher of English, in support of the specialised CNED course in French for immigrant kids, which the school paid for. The course is designed for home study, with or without help, and is taken at the kid's own pace. The arrangement would have continued, but, by the beginning of the second term, my daughter's French was good enough to rejoin her class, and the other teachers started giving her less latitude.
It helped of course that I was working at the school as well (after 20-odd years of formal education in the UK in French) so her teachers were also my colleagues, and I was also on hand to help. That meant that, if difficulties did crop up - which they did, especially in Maths - my daughter had teacher/family friends to consult with. It also helped then that I understood the rationale and ethos of the school in respect of dishing out marks, rather than assessing them in a vacuum or against her previous performance in school in the UK.
Hence all my questions to you. At the very least, it'd be worth asking the school if they can enroll your daughter for the CNED course (& you can learn alongside ....

). NB it IS all in French because the course isn't origin-oriented, so it's teaching French in the way that allows the child to understand what's happening in a French classroom, with lots of pictures and tapes (think they were cassette tapes - probably moved to CD/DVDs by now).
h