How to change dwg scale

Hi all,

Today I receive a dwg drawings of my architect. I want to draw in some extra furniture and other technical stuff to see if it all fits.

Unfortunatly i'm having troubles with the scale of the drawing. The dimensions in the dwg do not correspond to measurement or object I drew myself. It seems like there is a 1:45 scale applied to it. But I don't know to reverse it with affecting the entire drawing.

When I use the scale command all the dimension value become invalid.

Attached you can find the drawing.

FYI i'm using draft sight 2017 on my macbook.

Thanks for your help!

Kind regards

Mathieu

SolidworksDrawings And Detailing