This is a lovely lens from late 50s, with moderate contrast, quite different in the way it renders from the later 35/2.0. It really shines in bw, as your first photo shows. But avoid shooting in the direction of a light source, such as an open door or window, as it will flare badly.
The photo below was shot on a 35/1.8, and required a lot of post-processing to get the flare down so that you could make out the string quartet.
String Quartet by Steve Macfarlane, on Flickr
I really like the flare here. Wouldn't remove it even if possible. Gives an ethereal feel. Beautiful photo.
I haven't made many images with this lens yet and was expecting pretty low contrast, but it's a nice blend of old and new. The color shot I posted is pretty much straight out of the camera with no adjustments to contrast -- just a very slight bit of saturation.