Again this is just based on my observations. I could be wrong.
First I took the dimensions of the chair from the starter content. With no scaling, it measures approx. 113uu H, 81uu W, 81uu D. which in cm. would make it considerably larger than an average chair of this type.
I then took a picture of a room and compared the perspective with that of the perspective from a room I constructed in UE with the same dimensions. They were different until I multiplied the measurements I took by 1.25