It's definitely Shinra HQ, but I had a thought today that it could actually be this floor:
It's funny how your mind plays tricks on you. I could have sworn there was red carpet somewhere near the president's office, but the stairs are actually purple. The red I was remembering is just Jenova's blood:
The president's office is the only place in the OG where pillars like those in the image exist (as consistently). It's most likely the new version of the president's office, though it is strange to me how faithful Aerith's house is in comparison.
Although there is carpet that colour in the conference room:
And on floor 60 (as above, but also):
Now I'm not so sure. As usual, we need better images. Hurry up and snap some photos general public!
EDIT:
Mr. Ite said:
Gonna be the first to say that I prefer the OG's Shinra top floor. Big open pearl shit that's my villain HQ! The new one looks so cramped
As in the images above, we're coming at it (literally) from a different perspective. I'd say the pillars probably aren't any closer together than they were in the original going by the concept art, but the concept art feels more oppressive than a top down view because we can't see the roof in the original. The other OG image of the office is just as cramped looking IMO.