"LUCIOLE project" : Urban light optimised for the environment
City/Region : City of Lille , France

Outdoor night time lighting is very present in urban spaces. It’s a major part of ecological disruption and it negatively impacts fauna and flora.

LUCIOLE project aims to limit the impact of light pollution on bats, moths, and the nocturnal insects they feed on. This black network includes a 13-hectare perimeter within a larger biodiversity area of 40 hectares, which will be equipped with a public lighting system that is designed to facilitate the animal travel that traditional lighting impedes. This innovative project has benefited from European Union support, as a part of the ERDF "Nature in the City" program.

EU Green Deal Policy Areas Addressed
BiodiversitySustainable agriculturePublic space
Pathways followed
  • Implement sustainable procurement principles
  • Wisely select and apply smart technologies

Since 2001, the City of Lille has been promoting biodiversity with the objective of making the city sustainable and enjoyable for all citizens. In 2011, it adopted a “Biodiversity Plan”, one of the steps that will get her elected in 2012 « French capital of Biodiversity ». Today, Lille is particularly focused on continuing to implement actions to preserve and strengthen biodiversity throughout its territory.

To limit light pollution, Lille has taken many initiatives to create a “black network” throughout its territory. As noctural Chiroptera (bats) and entomofauna (insects) are directly impacted, Lille is moving towards innovative technologies.

The LUCIOLE project is focusing on the Deûle valley and the park of La Citadelle, identified as a major ecological and biological corridor and recognized for playing an important role in the preservation of these species.

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In Action

The City of Lille has been pursuing a proactive policy since 2005 to reduce light pollution and electricity consumption. For example, as early as 2005, the luminaires emitting light in all directions were removed. The public lighting of each site, whether it is created or renewed, is the subject of a detailed study aimed at optimising the levels of illumination and the amount of energy consumed, thus significantly reducing light nuisances. In 2020, public lighting in Lille will consume half as much electricity as in 2004 for a better service and despite the increase in the spaces to be illuminated.

The LUCIOLE project is financed 70% by the Region under the FEDER programme. The works amount is € 567,112 of which € 14,860 have been dedicated for initial impact studies. The regional subsidy will therefore be € 439, 708 on the total budget of € 628, 154.

The LUCIOLE project is an experimental project. Thus, the actions implemented may be repeated by other public and private actors involved in the project or as a result of it. In fact, the long-term preservation of biodiversity can only be envisaged if all the actors concerned implement solutions enabling the establishment of true biological corridors. As such, the project will eventually produce a compendium of recommendations to encourage other cities in that way.

This project is the first step in building a “black network” to be restored on a larger geographic scale. Ultimately, the challenge for the Metropolis is the complete restoration of the night continuity between the Deûle and the confluence of the Lys. Private actors managing lighting facilities are also concerned. This initiative makes it possible to sensitize citizens on this subject, allowing them to better know the effects of light pollution on fauna and flora and to reconnect with the observation of the night sky.


The park of La Citadelle plays a major role in the preservation of bats, since they stay there during their hibernation period. Even if the light does not disturb the bats during their hibernation period, outside this period it must be as harmless as possible to allow them to move, feed and reproduce.

There are 43 species of bats in Europe, 34 of which are present in France. If 21 of them are present in the territory of the Nord-Pas de Calais, only 9 species still exist in Lille. As the reappearance of bats will be the most visible outcome of this project, maintaining biodiversity is the safest way to encourage people to use the park in a more sustainable way.

The LUCIOLE project has led to the introduction of a new lighting system, a first in the fight against light pollution, combining the following principles:

  • An automatic motion sensor which is activated only in the immediate area where the movement has been made ;
  • In the absence of users, depending on the clock, the lighting is switched off or maintained with a very low luminous intensity in an amber light minimizing the ecological impact.
  • In the presence of users, the lighting adapts according to the seasons and varies in intensity and tint (from amber to warm white), to find the best compromise between comfort of the movements and minimization of the ecological impact.

A study carried out in 2010 had identified the different ecological continuities before a new study in 2015-2017 makes the measure of the impact of light pollution on the geographical distribution of bats in the territory possible. Thanks to that study, the City of Lille was able to identify the species of bats that require special attention.

The expected impacts of the LUCIOLE project are multiple on environment as well as for the inhabitants:

  • Strengthening the ecological corridor for the preservation of bats and butterflies at night by minimizing the light nuisances that cause problems for biodiversity because fragmenting spaces (travel/transit, feeding/hunting),
  • Demonstrate the value of technical solutions in innovative lighting for the protection of biodiversity,
  • Lead to an rise in the number of threatened species recorded in the territory,
  • Reduce energy consumption and aging of facilities (Efficiency energy and innovative lighting),
  • Improve the quality of life, ensure the safety of property and people.

An in-depth study is conducted this summer and another one would be put in place next September to measure the impact of these innovations on the return of the endangered species and especially on the Chiroptera (bats).

This assessment will check whether populations of lucifuge bats and their primary prey, heterocedars and chironomidal diptera (small-sized insects), are being re-implanted on the territory.

Challenges and lessons learned

Building a city attentive to everyone, dynamic and sustainable involves carrying out innovative and experimental projects that allow us to meet the following challenges:

  • How to reconcile human needs (security during the night) and fauna protection?
  • How to put technology at the service of environmental protection and biodiversity?

On the basis of the results of the ecological impact studies that will be carried out, simpler technological solutions to implement and manage can be deduced, particularly with regard to colour change. In the future, this could allow manufacturers to offer new systems at a more affordable cost.



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