The Parents' Associations of the European School run an informal network, Intercambio, to facilitate the exchange of students between the European schools. Not all schools are willing or able to accept exchange students, but most have been able to organise it. But this only works if host familes are found. Even if your child does not attend the same class or language section, and even if you can only host a student for part of the time, you will help a lot if you accept a student!
If you can imagine hosting an additional "family member" for a while, please check the actual requests for host families in Frankfurt here (access for PA members only) or contact us through firstname.lastname@example.org. Thanks!