https://www.bildungsserver.de/deutsch-als-fremdsprache-in-de...
https://www.bildungsserver.de/innovationsportal/bildungplusa...
It's complicated, because everyone likes to "look good", so publications always emphasize what they are doing, not what they aren't. E.g. in NRW, there are no classes for all pupils, just in grade 5 and 6 at some schools that have been selected for higher migrant population. So there are 180 remedial classes in NRW, which is laughable for a state of over 10 million.