It is NOT mandatory. This is courtesy of the press but there are no laws or regulations.

It's mandatory if the newspaper want to continue being a respected newspaper. So for all intents and purposes it's mandatory.

I can second this. You don't read the full names of suspects (!) in a newspaper in Germany. I believe this is actually due to the law here (e.g. if they're innocent, their name is not ruined). That is somewhat relaxed, as long as they're not a public figure (e.g. no one would say "Angela M. is suspected to be a physicist" if it's about the German Chancellor) and as long as it's clear from the article that they're not (yet) convicted.

Can't speak for the rest of Europe of course.

Well I dunno about germany but over here in the netherlands there's no real law about not using full names. However if a paper does use someones full name and then that person gets their reputation ruined they will usually get a lower sentence if guilty. The idea being that getting your reputation ruined is a punishment in itself.

There is currently a court case against a drugs kingpin where one of the reputable newspapers does mention his full name, but each time followed by "-- the suspect's lawyer has indicated the suspect has no objection to his full name being used" (once per article of course)

"Proper" newspapers don't, but yellow press (e.g. BILD) which is consumed by a large chunk of the German population doesn't really care that much about preserving privacy or correctly reporting on conviction status.