If I fill that amount of gas on my car, it would been half litre left before filling up

Same here, but the top figure of price would be higher.

My father filled gasoline when there were still sufficient fuel in his Toyota Auris car.
The reason for the higher price of the diesel, is because the government puts taxes on it, to deter people to buy a diesel passanger cars.
I don't remember the reasons, but a diesel engine is more polluting and noisy then gasoline engine, even if the first is more fuel economy.
But i hope that these taxes will deter people, here in Israel, to buy SUVs and SUT (An SUV with a pickup truck bed and a 4WD, off-road abilities a design, and a height, all of an SUV), which usually operates with a diesel engine.

Diesel can contain a lot of sulphur from the refinery, and this makes sulphurous acid in the exhaust. As well you get nitrous oxide in the exhaust gas as well. In a well maintained engine with working catalytic converters and a working soot filter in the exhaust these are at a low level with low sulphur fuel used exclusively. If you use cheaper fuel with a higher sulphur content, or are lax on maintaining the engine, then the pollution increases. The biggest cause is putting your foot flat on the floor, and labouring the engine, which then emits unburnt fuel into the exhaust, and creates soot that blocks the exhaust. As well short trips do not get the filters hot enough to clean themselves, and when they do get hot enough they run the risk of the matrix overheating and disintegrating if they have had a lot of short trips.

We used to have cheap diesel fuel back then. Now it is more expensive than the regular gasoline due to extra refinery process to remove sulfur content.

The crude used also has a input on the price of diesel. If you are using a sweet crude ( used to be mostly from the North sea fields) then there was very little sulphur in it. Most Middle East crude is higher in sulphur though.