I'm driving for the first time in Europe—in Munich, Germany—and I came across an intersection where there seemed to a "main" signal above, straight ahead, and a "side" signal to the right, near the bicycle lane. This side signal had the aforementioned road sign affixed to its pole—a red circle and X on a blue background with a right-pointing arrow. I found an example on Google Images but the site itself is down so I can't learn more about it, and I can't find any other site with this road sign:
Now, if this sign were standalone, there'd be less of a question about what it means. But here were my several thoughts:
It was a right turn from a smaller road to a main road, so it seemed unlikely that right turns wouldn't be allowed.
It was affixed to a side signal, so I thought it might mean to indicate that this side signal is a separate turn signal one should adhere to in order to make right turns (presumably to protect bicyclists and pedestrians).
A police car behind me, which I was nervously watching while waiting at the light, turned on its right-turn signal.
Was I in the right to make that right turn? (The police didn't stop me, but I heard that you just get ticketed in the mail for violations.)