It was a site to beyond as an estimated 3 million people marched the streets of Paris. This included world leaders from Germany, Italy, Israel, Turkey, Britain and the Palestinian territories.
Giant letters attached to a statue in the square spelt out the word Pourquoi?" (Why?) and small groups sang the "La Marseillaise" national anthem.
It was impossible to count the exact number of marchers spread throughout Paris, although it is clear the largest public demonstration in the history of France, more than those who took the streets following when Allies liberated the city from the Nazis in World War 2.
"Paris is today the capital of the world. Our entire country will rise up and show its best side," stated President Hollande.