The one on the left is in front. You can tell because the sun is to the left which is causing the shadows on the right building to go towards the right.
It seems some details of the building on the right are missing so that points to the one on the left being in front.
Judging from the light and shading, it must be the building on the right. Otherwise, how is it being lit up the way it is? Otherwise, the left building would be blocking the light.
Unless... we're being fooled by a highly zoomed picture and the right building is actually far behind enough to catch light from behind the left building. 2D often fails to reveals enough cues to know for sure. Even 3D can fool you sometimes.
If you look VERY closely, you can see that the building on the left causes some inconsistencies with the imagery of the building on the right. Come of it overlaps the right's windows, suggesting that the right is actually behind the left. But the lighting can be VERY misleading.
The one on the left is in front of the one on the right. It's only the upper floors that give it away.
I agree.
I say left because it's a little sharper, the one one the right looks out of focus, suggesting it's behind.
It all depends on how the camera is focused.