E. Krauss was a French camera and lens maker, founded in the late 1880s. Founder Eugen Krauss was the brother of G. A. Krauss. The company had a license to produce lens types of Carl Zeiss.
When Leitz named its 35mm camera it preferred "Leica" instead of "Leca" for not to collide with the name of E. Krauss' French "L´Eka".source needed