He was commander of the Württemberg Field Division in the Franco-Prussian War, fighting in the Battle of Wörth and, as part of the II Corps under the command of General Eduard von Fransecky, participated in the Siege of Paris. Obernitz received a grant of 100,000 Thalers for these services. On October 22, 1871, he became commander of the 14th Division in Düsseldorf. On June 11, 1879, he was appointed commander of the XIV Corps in Karlsruhe. Meanwhile, in June 1879 he was promoted to General of the Infantry and on March 22, 1884 he was appointed chief of the 4th (3rd East Prussian) Grenadier Regiment "King Frederick the Great". On August 18, 1886, he celebrated his fiftieth anniversary of service.