Starting school in another EU country
As EU citizens, your children are entitled to attend school in any EU country under the same conditions as nationals of that country.
They have the right to be placed in a class with their own age group, at the equivalent level to their class in your country of origin - regardless of their language level.
As an EU citizen if you move to another EU country for work, your children are entitled to free introductory tuition in your new home country to help them integrate and adapt to the school system there. Part of this initial training includes support to learn the language of your new home country.
Be aware that the school system in your new home country may be very different from what you are used to. In some countries, for example, children are separated very early into academic or vocational streams.
This is why there is no automatic EU-wide recognition of school certificates. In some countries, you must ask the national authorities to recognise your children's school certificates before you can enrol them in a local school.