How to SCALE large city with small details.

Hello,

I'm currently working on project, where main composition is large city.
My question is, how to properly scale the city - centimeters/meters/kilometers and so on.
I've found few articles, where people say, that REAL WORLD scaling is the way how to make things work fine in all cases. But problem is, if I want make large building, which could be in hundreds of meters, then put cap of tea on table in office room which is placed exactly in that big building, I'm not sure it would have worked well.

So I want make "Open World" scene for "movie", I want use UE4 to walk there and shoot/capture movements.

I want make this scene in Maya, and as soon as I know, making large scales, does not properly work in Maya.

So Am I supposed to down scale all things - kilometers=meters, meters=centimeters, and so on. Or is there any other way, how to make this scene?

The scene consists hundreds of buildings, small rooms, where people can walk.

Thank you for your help, Unity community.


John