Place Guillaume II, popularly known as the Knuedler, is the central square of Luxembourg City, covering an area of more than 9,250 m². Between 2020 and 2023, the square underwent a complete renovation: new paving, new tree planters, a playground, new lighting, a fountain, and modernized access to the LCTO tourist office. Architect Arlette Schneiders developed the concept, commissioned by the Ville de Luxembourg. The work was carried out in seven phases to allow the hospitality businesses and the weekly market on the square to continue as much as possible, and was completed in spring 2023.

As part of the renovation, the square received new, large plane trees. Van den Berk Nurseries supplied Platanus ×hispanica 'Malburg' with a trunk circumference of 70 to 80 centimeters. Due to the size of the trees and the narrow, historic streets in the city center, the trees were transported to the center at night in specially extended vehicles under police escort. Existing plane trees that could not return to their original location were replanted elsewhere in the city at the time.

Plane trees are highly resistant to paved surfaces and air pollution, and their large leaf area captures fine particulate matter. Due to their mature size, they cannot be planted everywhere in the city center. This square does have the space: the crowns provide shade over a large part of the square, lower temperatures on warm days, and break up the otherwise predominantly paved space with visible greenery.