Otto Wegener (20 January 1849, in Helsingborg – 4 February 1924, in Paris) was a Swedish-born French portrait photographer.
[1] He taught photography to Prince Eugen, Duke of Närke of Sweden and Edward Steichen was one of his assistants.
He is most famous for his portraits of Isadora Duncan and Marcel Proust, who was also a friend, and Paul Verlaine, who posed in 1893 as part of his preparation to become a candidate for membership in the Académie Française.
The error came about after the brothers, Georges and Oscar Mascré, began using Pirou's name without his permission, and later advertised themselves as "Otto-Pirou", in an obvious reference to Wegener.
He had three sons, including Maurice Otto Wegener (1875-1918), an aspiring artist who reportedly died of physical and mental exhaustion, resulting from the war.