More info: The public square in the 4th arrondissement of Paris that is now the Place de l'Hôtel de Ville (City Hall Plaza) was, before 1802, called the Place de Grève. The French word grève refers to a flat area covered with gravel or sand situated on the shores or banks of a body of water. The location presently occupied by the square was the point on the sandy right bank of the river Seine
The principal reason why the Place de Grève is remembered is that it was the site of most of the public executions in early Paris. The gallows and the pillory stood there.