This is a poster displayed in a First World War exhibition comparing the impact on twin towns in the UK, France and Germany. Nobody who came could explain the meaning of these white hook symbols.
I would assume they are a reference to the Treaty of Versailles, specifically The "ยง"-paragraph symbol is often used as symbol for the profession of law, similar to the scale. It might refer to the "Kriegsschuldparagraph", the War Guilt Clause, which placed the blame for WWI solely on the shoulders of Germany. Looking at the trains in the background, which seem to be moving away from the viewer and look like bulk cargo trains, it might be a reference to the French occupation of the Ruhr area in 1923 and the shipping of coal back to France.
