The Jacobacci brand was founded in the Parisien district of Menilmontant during 1920s by Vincent Jacobacci. Jacobacci was an Italian immigrant from Catania, who began by making banjos and  guitars. Vincent's son Roger Jacobacci, decided in the early fifties to start making  electric guitars, initially by adding pickups to the existing Jacobacci acoustic guitars.

Jacobacci built guitars for the Major Conn Paris store following an agreement in 1956, and these guitars have the brand name Major. Major models included the Royal, the Soloist and the Super Deluxe. Other models included the semi-hollow bodied Texas and the solid bodied Ohio. Some famous French rock and roll bands (like Johnny Hallyday, the Pirates and the Vatours) played the Texas and Ohio models, increasing the desirability of Jacobacci guitars with the French public.

After a few more models the partnership with the Major Conn store stopped in 1965, and the Jacobaccis (Roger was joined by brother André) reduced their range to concentrate on a smaller number of high quality instruments - like the R1 thin-line. At first these guitars did not bear a brand name, but from around 1966 the brothers started using Jacobacci on the headstock. Later models appeared in the 1970s and 1980s including the JB200 bass and the JD80 and JJ guitars.

Around 10,000 electric guitars and basses were produced by the two brothers in the period from the 1950s to the 1980s.

Sources:
http://lesguitaresjacobacci.free.fr
http://fr.wikipedia.org/wiki/Jacobacci