The GTL-Ville is an online experimental platform for the real-time collection and visualization of traffic data for the city of Grenoble in France. The platform processes real-time traffic data to calculate macroscopic traffic indicators such as flow, density, speed, traveling time and vehicle emissions. The platform was developed by the ERC project Scale-FreeBack, to showcase the various innovative methods and techniques developed by the team, such as sensor location, density reconstruction and prediction, and travel time estimation.