There are various rumors about this, particularly in the previous East Block. The goal of the activists is supposed to educate a more tolerant view for the children already in the early childhood. Opponents argument mostly by the (constitutional) rights of the parents to choose the education of their children. In the background, there is a kulturkampf between the liberalism and the traditional, mostly Christian values.
Here I found a reference that the local government of Berlin actually financed this, but it is not clear, how extensive is this practice. There is also a recent news about a new Hungarian law, essentially forbidding LGBT education until the elementary school.
Googling for that did not reveal too much for me, possibly I did not use the correct search keywords. Beside that, finding a trace by Google for something is much easier, than proving that it does not exist.
What is the reality?