I was more than a little confused about the context. Here’s what I found:
>The three people in Cartier-Bresson’s photograph are a woman being publicly exposed as a Nazi collaborator; the woman accusing her, dressed in black; and a gaunt, serious-looking man who is seated at a desk and clearly an authority figure. The identities of the two women are not known, but Cartier-Bresson noted that the accused woman was Belgian and ‘a Gestapo informer [who was] recognised before she could hide in the crowd.’
>The man has been identified as Wilhelm Heinrich van der Velden, a young Dutchman who had been appointed camp commandant at Dessau by the American military. Van der Velden had himself been recently liberated from the Westerbork concentration camp, which was set up by the Nazis in the Netherlands.
>At the moment the picture was taken, the informer stands with her head bowed in shame while the woman accusing her bares her teeth and raises her arm, filled with rage and the desire for revenge. Their contrasting expressions symbolise the feelings of people on the winning and losing sides in a long and devastating war: the triumphant anger of people finally liberated from the tyranny of Nazi control and the humiliation of the German defeat.