What does this traffic sign indicate?

You answered correctly! This traffic sign indicates a hydrogen filling station. In Germany, the "H₂" symbol specifically points to a refueling station for hydrogen-powered vehicles, not for natural gas or auto gas. Knowing the difference is important because each type of alternative fuel has its own designated sign, and you need to recognize them to avoid confusion, especially with similar-looking symbols for other fuels. This helps drivers of hydrogen vehicles find the right refueling locations.