Parc de la Citadelle & Pont Léon Jouhaux

Since 2005, the city of Lille has been actively implementing solutions to reduce its carbon footprint and protect the environment. The local authorities are progressively replacing all lighting fixtures in the city with more energy-efficient LED luminaires managed by control systems that adapt the light to exactly where it is needed and when. These actions have enabled the city to cut their energy consumption by 50% in 2020 compared to 2004, while improving the quality of light.

La Citadelle, a 110-hectare park incorporating the city’s zoo, is a popular public space for residents who regularly go for family strolls, runs or bike rides. It is also home to a wide range of flora and fauna with over a 100 different species of animals, including vulnerable species like bats - and they all need lighting that respects their natural rhythms. Research suggests that the light pollution produced by blue-rich and bright white bulbs can be more disruptive to wildlife. 

Committed to preserving this wildlife, the city adopted a “Biodiversity Plan” in 2011. In 2017, they launched the LUCIOLE (Lumière Citadine Optimisée pour L'Environnement) project to preserve the park’s animals and plants, including the 9 remaining species of bats that live there.
 

Urban lighting for a harmonious co-habitation

The objective was to create a nocturnal corridor in the park with a new lighting solution that would keep the park’s animals and plants healthy and happy as well as help it achieve its environmental goals and ensure that citizens feel safe and satisfied. A solution that adapts the intensity of the light according to the different needs of the area and the colour temperature was vital. 

The project managers opted for the CITEA luminaires fitted with our FlexiWhite solution and motion detection sensors to switch automatically from amber lighting to white light on sensor detection, in order to protect the fauna and flora while ensuring human safety and comfort. 

The colour temperature is programmed to adapt according to the seasonal behaviour of bats, who usually emerge from their roosts approximately 30 minutes after sunset to forage. 

From April to November, when sunset is later and bats are the most active, only the amber LED (3,000K) modules switch on and off to protect them. 

Then from November to March, when the bats are hibernating, the LED modules with amber and white LEDs (2,200K) switch on and off depending on the time of night and the presence of people. 

Locals who commute early in the morning and late in the evening benefit from optimum visibility. During the night, when the lighting switches from white to amber, the local wildlife can sleep soundly. If a pedestrian or cyclist arrives, sensors detect their presence and the white LEDs temporarily switch on to guarantee a safe and comfortable passage.