Is it true that indexed movies in Germany are not actually banned?

"The Index" is the colloquial name for the "List of Media Harmful to Young People", which is maintained by the German "Federal Review Board for Media Harmful to Minors". It contains not just movies, but also video games, audio recordings, and printed media (though there are more movies on the Index than the other three categories put together).

This section of the German legal code lists the consequences of a work getting added to the Index. It's unfortunately in German, but thankfully Wikipedia has a translation:

1. It must not be sold, provided or otherwise made accessible to minors.
2. It must not be displayed where it can be seen by minors. This would, for example, include playing an indexed game in the presence of minors (e.g. streaming gameplay over the internet).
3. It must be sold within a shop in an area accessible only to adults ("under the counter"). Basically selling indexed titles per mail order is illegal, however it is permissible if the package may be handed over only to a specified adult person, who has to present ID.
4. It must not be rented out, except in a shop inaccessible to minors.
5. It must not be imported by mail order. In this case an adult buyer (importer) is not subject to penalty, if he himself has no intentions of further dissemination it to others or minors.
6. It must not be advertised or announced in a place where the announcement or advertisement could be seen by minors.
7. If it is for one of the above six causes, production, acquiring, and holding in store are subject to penalty, too.

In short: yes, movies on the Index are not actually banned in Germany. The purpose of the Index is to make it as hard as possible for minors to stumble across the works listed on it, but adults may still freely purchase them.

I found this on Schnittberichte:

9. Is the purchase, sale and ownership of indexed media illegal?

Definitely no. For example, you can buy and sell indexed films and also buy and sell indexed games. Ownership is also not a problem. Considering the advertising restrictions on indexed media and the legal requirement that these contents should not be offered for sale by underage persons, none of this is punishable.

Disclaimer: I don't speak German, and I had Google translate that page for me.