One very brutal occupation of a city was the "Rape of Nanking". After Japanese captured the city in 1937 the Japanese Imperial Army spent weeks killing between 200,000 and 300,000 people and raping between 20,000-80,000 women. I do not know how large the "Rape of Germany" was and do not know any significant statistics of information regarding it however the "Rape of Nanking" was a very wide scale brutalization and may be comparable with the "Rape of Germany" that you mentioned.