German journalist; born at Höchberg, Lower Franconia; Oct. 29, 1831. After having acquired considerable wealth as a merchant, he founded in 1856 the "Frankfurter Zeitung," a newspaper published in Frankfort-on-the-Main; it soon acquired a leading position in southern Germany, especially in the commercial world. Since 1867 Sonnemann has been its sole proprietor and editor.
From 1871 to 1876 and from 1878 to 1884 Sonnemann was a delegate in the German Reichstag, as a member of the People's party (Volkspartei), for which his paper has always been a representative organ. At his first election (1871) he defeated Baron Rothschild, at the second (1874) Lasker. In 1884 he was defeated by the Social Democrat Labor.
Sonnemann is at present (1905) a prominent member of the aldermanic board of Frankfort-on-the-Main.
- Brockhaus Konversations-Lexikon;
- Giesen, Zwölf Jahre im Reichstage. Reichstagsreden von Leopold Sonnemann, Frankfort-on-the-Main, 1901.