Mario is in Hannover to work as a miner but after loosing his job he decides to go back to Italy. When Totonno steals his passport to avoid the police and later on he offers him a new job as "magliaro" (cloth seller), Mario changes his mind and decides to follow Totonno to Hamburg. In Hamburg, Totonno and his friends have to sell Mayer's cloth but they meet with the hostility of a Polish gang and Mario falls in love with Paula Mayer.
This is an Maico M250, early version. The bike is very similar to M175S. Production period of the bike was only from July to November 1954. The cylinders of Maico M175 iron barrels have 12 cooling fins, the M250 engine has 13 fins. The picture above obviously shows 13 cylinder fins.
It appears http://en.wikipedia.org/wiki/BMW_R60/2 that production of R60/2 only began in 1960. The film was shot in 1959 (Italian release: september 59). Wouldn't in fact the bikes depicted above be R50 or R60?