German copyright law has no Fair Use. There are copyright exemptions for private or academic use, but commercial use has no such exemption. Books have special protection even according to § 53 (4) b).

And yes, it's the duplication which is illegal, not the publication of them.

[1]: https://www.gesetze-im-internet.de/urhg/__53.html

It does not have "Fair Use" directly, but things like parody or commentary are allowed to use portions of copyrighted work. There a quite a few paragraphs detailing exceptions: https://www.gesetze-im-internet.de/englisch_urhg/englisch_ur...