The standing light feature is what we in the US call parking lights. Basically the bulb in the turn signal for the USA has two filaments instead of one like in europe. When you turn your headlights on one filament comes on with the headlight (it also comes on without the headlights on one click of the headlight switch) and the second filament only comes on for signalling.
There are a few europeans who like this feature becuase of the safety aspect and because it looks "American" so european aftermarket sellers have started to provide europeans with corners that have a standinglight feature that mimics the US parking light by drilling an extra hole in the turn signal and mounting a small bulb in it and then providing instructions on splicing this small bulb with the european citylight wires.
The city light feature in europe is a small bulb thats inside the headlight on european cars. It comes on with one click clockwise of the headlight the same way the parking light comes on in the USA. If you have euro headlights in the USA you probably have a mounting for a city light if you look closelyat your euro headlight main reflector. The small bulb of the city light is the same as the small bulb of the standinglight.
Now stay with me....
if you are in the USA and you have euro headlights and want to activate the city light feature, you can get the bulb holder and bulb, fit it into the reflector and splice it to the third wire going to your turn signal. That third wire provides the power for the second filament in the turn signal bulb for the US parking light.

Hope you got it. Your profile doesn't indicate where you are from. Considering that you don't know what parking light are I am assuming you are probably from a non-US territory so hope this explains things...