Paris accelerates its low-carbon transition by testing the first urban service for accurate measurement and tracking of CO₂ emissions

Continuously quantifying and mapping CO2 emissions across a territory: a world first developed by our start-up in partnership with the Laboratoire des Sciences du Climat et de l’Environnement (LSCE). Tested by the city of Paris, this major innovation in the fight against climate change has enabled precise measurement and analysis of the capital’s evolving CO2 emissions over several months.
The mission

“CO₂ meteorology” using 3D models and accurate measurement to guide climate action in real time

The goal in Paris is to build a carbon-neutral, 100% renewable-energy city by 2050. The capital needed a tool for measuring local greenhouse gas emissions that could meet the challenge of its transition to carbon neutrality. It wanted to work with and the LSCE, as Yann Françoise, the city of Paris Climate, Energy and Circular Economy Manager, explains: “Paris has supported the project since its creation in order to benefit from the latest scientific advances in favour of the climate transition in Paris. It will open new avenues for managing the low-carbon transition, quickly evaluating the impact of projects and engaging in a new form of dialogue with Parisians.”

Traditional methods for estimating CO2 emissions in urban environments are based on inventories that offer a picture of emissions two or three years late. Local authorities mostly have to rely on simple Excel spreadsheets containing meagre field data or statistics, sometimes supplemented by default values, which take a long time to collect, process and check. Knowledge of local greenhouse gas emissions is thus always subject to a time delay.
Our response

Offering a dynamic, continuous vision of CO₂ emissions at the scale of the city and the LSCE have jointly developed the first real-time system for monitoring CO2 emissions and managing the low-carbon transition. It has been deployed in the form of a demonstrator at the scale of central Paris and the whole urban area.
The pilot project’s science and technology chain is based on:
  • data measured by the LSCE’s existing network of sensors and the new generation of sensors built and installed by,
  • quality control of the urban data generated,
  • a meteorological model,
  • modelling of CO2 dispersion in the atmosphere,
  • generating inventories of emissions across the territory and analysing the results,
  • designing indicators and a method of representing the results on a monthly scale.

Identifying the origins of emissions to better reduce them and keep citizens informed

By obtaining an accurate view of emission sources, the local authority can decide on the best actions to adopt, inform its citizens and raise their awareness of climate issues and target the times, areas and zones with the highest CO2 emissions.
“Our technology stands out by offering a dynamic vision almost in real time. The LSCE’s high-precision measuring stations, and our own, detect clouds of CO₂. We can then model the weather to determine where they are coming from.” David Duccini, CEO of

This world-beating innovation was recognised by the World Meteorological Organization nearly three years ago.
descriptive geographical databases in constant use



The number of buildings and companies whose local carbon emissions are analysed


million estimates of CO2 emissions produced every day in Ile-de-France
The results

A one-off drop in emissions observed in 2020 during the two lockdowns

An analysis of CO2 emissions carried out during the second lockdown in France, from November to December 2020, revealed a significant drop in emissions of around 35% for the city of Paris and 22% for the Ile-de-France region.

The first lockdown, from March to May 2020, caused a sharper fall in emissions of around 54% for Paris and 42% for Ile-de-France. The less pronounced reduction in emissions during the second lockdown is partly due to the fact that economic activity and road traffic remained at a higher level at the end of 2020.

“The lockdown led to a very brief drop in emissions, and to meet the City of Paris' reduction goals, continued efforts with systemic changes will be required”, points out Philippe Ciais, a member of the French Academy of Sciences, the LSCE research director and a project participant.

A pilot observatory for measuring CO₂ emissions

The partnership project between, the LSCE and the city of Paris also ultimately aims to establish a pilot observatory to measure CO2 emissions in Paris and the Ile-de-France region. The goal is to monitor the evolution of greenhouse gas emissions and track the impact of measures to reduce CO2 emissions. For Yann Françoise, “obtaining emissions data in almost real time is a useful innovation for Paris and all other cities.”

A network of 14 sensors deployed so far out of a planned 17

Additional sensors will be installed to provide the local authority with:
  • More frequent data: The volume of CO2 emissions originating from fossil fuels with at least monthly frequency would enable the trends operating across the territory to be estimated;
  • More precise, spatialised data: A geolocated register of CO2 emissions and the potential for reducing them, with estimates that will target uncertainty levels below 10% – these can be much higher with current methods;
  • Contextualised data: The trial aims to determine the relative contributions of emitting activities (buildings and road transport in particular) and the decisive factors.



Drop in CO2 emissions in Paris in 2020 during the second lockdown



Drop in CO2 emissions in Paris in 2020 during the first lockdown


sensors ultimately, of which 14 are already in operation
Learn more
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