I feel that this sign could be commenting on one of two situations in Germany. Most likely, it is reference to the impending implementation of tuition at German universities. Rich parents for all would thus make payment of said tuition easier.
I also think that this sign could be commentary on the educational gap between rich and poor that is a problem, well, most everywhere as far as I can tell. However, I think that this is less likely the intended meaning of this sign and more likely the meaning that I would like to ascribe to it, seeing that the educational gap between rich and poor is one of my pet peeves/favorite topics.