There is no standard height-
The electrician wants to know the location of the junction box, not the light. You care about the location of the light.
It depends on whether the light is up or down facing, the distance of the lamp from the junction box (away from wall and above or below box), and other things.
Best is get the physical fixture and place it on the wall to determine best height.
Next best is to get a cut-sheet from the mfg. and try that way.

thanks! And in you opinion which is better for comfort and function up facing or down facing?

You are welcome. It depends on the fixture and other lights in the space. Typically there is not alot of difference if you set the height so the light washes the side of your face and does not light too much from top or bottom.

got it :)