This is the Al Merjeh or Martyrs Square. It used to be the centre of the city, which it no longer is. The martyrs are the people killed when the French mandate came to an end. The river Barada flows - rather channelled - along a column that must be the monument proper.
From the Enc. Britannica article about the city: With the departure of the Ottomans, Damascus entered a new era, during which it has changed in size, physical appearance, and political role. An independent Syrian state was declared in 1919 with Damascus as its capital; Fayṣal was proclaimed king early in 1920. A few months later, the French, with a League of Nations mandate, defeated his army and entered the city. Damascus resisted the French takeover, and an uprising in 1925 was put down only after the French bombarded the city. The years of the French mandate over Syria, from 1920 to 1946, were a period when Damascenes, along with their fellow countrymen, struggled for their nation's independence and for the broader goal of a single Arab state. The Baʿth Party, devoted to that goal, originated there during World War II. The mandate period lasted until April 1946, when, responding to a United Nations resolution, French troops finally left Syria. Once again Damascus was the capital of an independent Syria.