Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download Office Mega Kit Free.
Office Mega Kit v1.0
The Office Mega Kit is a bundle pack including all the content from the following kits:
Office Level Kit
Office Hall Stuff Pack
Office Cubicle Kit
Office Bathroom Kit
Office Cafeteria Kit
That’s more than 250 prefab parts and pieces for building your office game environment in Unity 5. The Office Mega Kit is a savings of $15 over purchasing the kits separately.