The historical department of the French Ministry of Defense has scanned and posted the secret military file that was used to wrongly convict Captain Alfred Dreyfus of spying for Germany in 1894. The full file, which contains over 500 documents, is available here and here (as a more easily navigated Google doc). Dreyfus was a French patriot who, despite being railroaded and then wrongly imprisoned, returned to French military service in World War I.
For more detail on the Dreyfus affair, see this article in The New York Times.