1950s Berlin street scene

Done by a street artist in Berlin in late 1950's. Purchased by U.S. Army soldier while stationed in Germany. He sent it and four 8x10 prints by the same artist home to his mother. She kept the original and the prints in her attic for 40yrs. I purchased it and the four prints in 2004 from her son at an estate sale. The original frame had deteriorated so I had it professionaly reframed and put behind glass to preserve it because it's fairly fragile. It is done on paper on wood. Want to know anything you can tell me about the artist and the value for insurance purposes.