On 10 December 1891, Schwartzkoppen was appointed as
military attaché at the Embassy of the
German Empire in Paris, maintaining relations with the
French Republic. It was his second diplomatic posting to Paris. In addition to performing formal representational and liaison duties, his subsidiary task was to obtain secret information on the
French Army without the knowledge of the German ambassador resident in Paris. Instead, Schwartzkoppen reported directly and in confidence to the Director of Military Intelligence in Berlin. As a result of his spying, he became involved in the Dreyfus affair. In 1894, he received an anonymous offer for the purchase of rather insignificant
military intelligence, outlined in an unsigned
bordereau. The torn paper was recovered from Schwartzkoppen's wastebasket on September 25 by a cleaning woman who was a French agent and became the key evidence of Dreyfus's arrest and conviction for
treason, as it was supposedly in the handwriting of
Alfred Dreyfus. Serious doubts regarding the guilt of Dreyfus were raised during his trial. Later investigations showed that Schwartzkoppen was receiving intelligence not from Dreyfus but another French officer,
Ferdinand Walsin Esterhazy. Schwartzkoppen himself confirmed Dreyfus's innocence in his memoirs, which were published posthumously in 1930. In the 1890s, Schwartzkoppen had an affair with Hermance de Weede, the wife of the Counsellor at the Dutch Embassy in Paris, and a large number of their letters were intercepted by the authorities. Also intercepted was the correspondence between Schwartzkoppen and a popular figure in Parisian diplomatic circles - the Italian military attaché, Lieutenant Colonel Count
Alessandro Panizzardi. Italy and Imperial Germany were then formally linked under the
Triple Alliance of 1882 and letters between the two attachés record that they freely exchanged intelligence and cooperated on espionage matters. The letters also contain bawdy comments and erotic endearments which indicate that they too were having an affair. The Schwartzkoppen and Panizzardi material was withheld from the Dreyfus defence team in 1894 but was later discussed in a closed session during the 1899 retrial. While neither officer had anything to do with Dreyfus, the correspondence lent an air of truth to other documents that were forged by prosecutors to lend retroactive credibility to Dreyfus's conviction as a spy. Some of the forgeries even referenced the apparent affair between the two officers. In one, Panizzardi supposedly informs Schwartzkoppen that if "Dreyfus is brought in for questioning", they must both claim that they "never had any dealings with that Jew.... Clearly, no one can ever know what happened with him". The letters, real and fake, provided a convenient excuse for placing the entire Dreyfus dossier under seal because the exposure of the liaison would have "dishonoured" the German and Italian militaries and compromised diplomatic relations. ==Later life and death==