On the question of whether loot boxes should be considered a gamble, I have already written something here. A few provocative legal versions of the Free2Play model, however, can be found in this article.
Recently, I also gave an answer to my esteemed colleague, Neden hurabasic, who conjured up an article at Bild+. You can read the article here, but you need a daily pass from the Bildzeitung for this.
“So far, there has been no administrative decision on the subject as far as I know,” explains IT lawyer Marian Härtel. “However, the legal definitions and decisions on poker and gripping arm games suggest that courts would probably decide against loot boxes.”
Incidentally, Google has now also reacted to the issue and is also demanding that the chances of loot boxes be disclosed. See this article.