jewishgen.org gives his date of birth as 25/10/1900 and says he married Terci Lustig in 1927. The Breslau synagogue address (ca 1930) lists his brother Norbert and sister Emma, and lists a Gustav Guttmann born 24/10/1899 married to Therese Lustig living at Kopischstrasse 82; I assume this is the same Gustav.

Gustav and Therese lived at Kurasserstrasse 153 when their German nationality was annulled.