Curiously in Germany Diesel is actually cheaper than regular gas at the gas station. This is because it's taxed differently. So a Diesel car saves Germans money two times (less fuel consumption and less price per tank) as compared to a gas engine car, which is why they are extremely popular over here.
That said, on an absolute level in Germany Diesel is still about 1.7x more expensive than Diesel in the US and about 2x more expensive than gas in the US.