Bob Hanson said: "... a ... cable-operated front derailleur from Simplex. This was made from 1952 to 1956. .... Except for Campagnolo's Gran Sport, most all other front derailleurs of this era were still rod-actuated changers. ..."
Simon Bird mentions a cable-operated Huret front derailleur from that era. Others include
Rosa, starting around 1932
Cyclo (Benelux) starting around 1951
La Jolla California USA