The invention of the Leica camera in 1925 a speed, an usefull and discreet machine gives new opportunities to many photographers helping them catching ther energy of crowds or cities. The French and American photographers will be the first understanding and rising up the possibilities given by the Leica. The French Humanist School (Robert Doisneau, Edouard Boubat, Willy Ronis) build just after WWII will immortalize with tenderness the daily life stories of the old Paris. The New - York School as the American historian Jan Levingstone says in 1992 shows the beauty but also the brutality with a political commitment showing people moving inside an unhuman universe leaded by progress. Everything begins in the 1930's when a German association names "Workers International Relief" decides establishing itself in New - York city. It put together professional an non prefessional photographers following the goal becoming film critic and promoting Russian propaganda movies. This association will take another name in 1936 the "Photo League" until 1951 when it decide dissolving itself. The New - York school just build after take the succession but doesn't follow the same purpose. Like in the New - York School of painting spontaneous and objectivity play an important part in picture making.