How can I create this effect?

[jam_ed]

Does someone know how i can render a glass facade like this example, with a soft light and fading silhoettes behind it?

[CJI]

That is a heavily photoshoped and stylised image. The people are almost certainly silhouettes comped in photoshop.

 

Light your interior as you want, Render, then photoshop. Comp your silhouettes over the top using an overlay layer or whatever looks best then play with the opacities to get your varied intensities to simulate their depth in 3d space behind the glass. Thats the way i would do it for this example. Quick and easy.