Installation comprising a wall equipped with at least one window system, said window system comprising: - a window disposed in said wall, said window being delimited by substantially horizontal upper and lower edges disposed one above the other, the window being provided with variable opacity glazing; and - a control device for variable opacity glazing associated with the window, said control device comprising a control box; the control box being secured to the wall above the top edge of the associated window, a length of said control box being disposed substantially parallel to said top edge, dimensions of the control box perpendicular to its length being less than 10% of said length, the installation further comprising a ventilation vent associated with the window, said ventilation vent having an elongate shape extending substantially in a first horizontal direction parallel to the wall, so that, in a first configuration, said ventilation opening and said wall define a space of elongated shape located above the upper edge of the window, said space extending in a second horizontal direction perpendicular to the first horizontal direction, the control box of the control device associated with said window being received in said space. - a window disposed in said wall, said window being delimited by substantially horizontal upper and lower edges disposed one above the other, the window being provided with variable opacity glazing; and - a control device for variable opacity glazing associated with the window, said control device comprising a control box; the control box being secured to the wall above the top edge of the associated window, a length of said control box being disposed substantially parallel to said top edge, dimensions of the control box perpendicular to its length being less than 10% of said length, the installation further comprising a ventilation vent associated with the window, said ventilation vent having an elongate shape extending substantially in a first horizontal direction parallel to the wall, so that, in a first configuration, said ventilation opening and said wall define a space of elongated shape located above the upper edge of the window, said space extending in a second horizontal direction perpendicular to the first horizontal direction, the control box of the control device associated with said window being received in said space. said control device comprising a control box; the control box being secured to the wall above the top edge of the associated window, a length of said control box being disposed substantially parallel to said top edge, dimensions of the control box perpendicular to its length being less than 10% of said length, the installation further comprising a ventilation vent associated with the window, said ventilation vent having an elongate shape extending substantially in a first horizontal direction parallel to the wall, so that, in a first configuration, said ventilation opening and said wall define a space of elongated shape located above the upper edge of the window, said space extending in a second horizontal direction perpendicular to the first horizontal direction, the control box of the control device associated with said window being received in said space.