It is not banned in Germany, though there obviously exists a stromg social stigma if you chose to display it in your living room.

The legal situation is this:

The free state of Bavaria has inherited Hitler's assets. Including the copyright to My Kampf.

Bavaria does not allow any reprints, unless for scientific purposes with commentary alongside the text. Obviously publishers abroad don't always care about that.

(Interestingly, publication in the US and England is actually legal, since the rights to publish in English were sold long before Hitler's death).

Other than that copyright issue there is no legal mechanism in place to ban Mein Kampf. People have been buying, bequeathing and selling unannotated versions (of which there are many around, the Third Reich isn't some fantastically distant past, after all!) without problems.

The question that has been popping up in political circles every now and then and that has reached some urgency now is how to proceed.

Because Hitler died in 1945, his copyright ends on January 1st, 2016.

There are people calling for special legislative action, but I doubt it's coming.