I'm sure there are other examples that others can discuss, but one that immediately comes to mind are the widespread rapes that occurred in France in late 1944 and early 1945, especially Normandy and Brittany. Before going any further, I should mention that these took place in the context of large amounts of consensual sex between American GIs and French women as well as large amounts of prostitution (some more willing than others) between the same, and that they took place in a period in which these areas were truly hurting in terms of food and heating material necessary to survive the winter (which calls into question exactly how consensual some of the consensual sex was). Further, from the American perspective, France had been, quite purposefully, portrayed by both the military and the previous WWI generation as a place of debauchery in which French girls were willing participants in the sexual escapades of American boys. To an extent, there is still this view of the French in American culture, but at this time, such a view was actively cultivated by the military, and it extends to the entire country, although, it must be admitted, the city of Paris received a large focus. The reports of American patrols or units who were ordered from one section of Western France to another, but who "got lost" and "wound up", "all of a sudden" in Paris (despite it being hundreds of kilometers out of their way) are too numerous to count. But I digress ...

Both French and American leaders saw the rape accusations in Western France as a real problem; the French leaders also saw the consensual sex as a problem since it had the effect of emasculating French men vis-à-vis their American counterparts, although surprisingly, no one really cared about the prostitution beyond it being seen as a health issue (VD - as it was known then - was a huge problem among soldiers). American leaders tended to protect the image of the [white] American soldier as a liberator by pinning the majority of the rapes upon African-American troops. African-Americans, because of their position in the military, made especially easy targets, despite the fact that there is no real evidence that they committed rape with any more frequency than their white counterparts. First, African-Americans tended to be put into supply and logistics rolls - meaning they worked behind the front and tended to not move around as much as white soldiers on the front line. While a white soldier would be in and out of a village in as little as a day or two, African-American troops might spend weeks in the same location, making them easier targets for false accusations, which most assuredly occurred. There are numerous accounts of women who did not at first report a rape (i.e. they said sex with the black GI was consensual) until cajoled into it by family members, sometimes even returned husbands, at which point the African-American GI would be arrested and sometimes even executed very quickly. There are other reports of women claiming rape, very explicitly stating that it was pitch black out (remember there was not always electricity in these villages, those that had previously had it might have lost it in the bombing campaigns that occurred before D-Day) and they couldn't see four inches in front of their face as they were raped in the middle of the night in an interior room where the candles had already gone out. Some of these women would then be brought before a line of black GIs and told to pick out their rapist, and they ended up picking out someone they had seen at some other time or a random person completely, despite their own protests that they weren't in any way certain and despite the black GI's obvious protests of innocence. Other scenarios of a similar nature in which American leaders basically assumed that it was only black GIs committing these crimes despite evidence that whites were also doing the same occurred the entire fall, winter, and spring. To a lesser extent, French racism was also a factor, but I cannot exactly recall how my source discusses that. This French and American racism was combined with the American military leadership's desire to protect the image of the white liberator who was saving French girls (as opposed to the American imperialist taking their "prerogatives" with a conquered people) to turn the problem of American sexual violence into a problem of negro sexual violence.

To this day, these rapes are one of the lessor known instances of American war crimes during the war.

The seminal work on this is Mary Lou Roberts - What Soldiers Do. I cannot recommend it highly enough. The author (I've met her) is a wonderful (and hilarious) person. The book is one of the funniest academic works I've ever read (at least the first portions where she's talking about consensual sex and cultural/linguistic misunderstandings - it gets a lot less funny by the third section, when she deals with rape)