Disclaimer: I'm not a lawyer and don't live in Germany.
I know of 2 possible legal issues with this (there might be more):
Bildrechte (or photograph rights). This says something along the lines that you're not allowed to publish images of someone's face when this might damage them in some way (privacy, financially, reputation, etc.).
The second is that images of someone face can be traced to that person, which makes them count as personal data under EU law. This means you're not allowed to process them (let alone publish) without explicit permission. This runs against the rights of free speech and journalism, so (I assume) there's a lot of compromises and gray areas here. More on personal data can be found here: http://ec.europa.eu/justice/data-protection/
As far as I know these laws apply equally to famous and non-famous people.