The used materials and the typically used fire countermeasures are a longer known problem.
Seeing that it burned bottom-up, outside-only and very dark, cloudy fumes indicates the type of the fire pretty much.
Second half of this german report (likely that german construction/delivery has been user) shows a burn test which escalates quickly.
https://www.youtube.com/watch?v=ekD7vq18suA
RT reports that the building saw some reignition.