The Lab
An independent research laboratory that advises.
Millennia Lab is an independent research laboratory based in Paris. It studies the conditions of a robust transition: environmental, material and economic. Its programmes build models of food and land systems, forests and wood products, construction materials, accounting standards and national economies. Each asks what current figures leave out (the carbon value of land, forest carbon lost at harvest, impacts outside the accounting boundary, the safety margins that efficiency removes) and what that omission costs.
The lab builds its own models, rebuilds published ones so they can be verified, and couples models with partner institutions. Predictions are written before runs, and uncertainty is carried through to the result. The lab works with universities and international research institutes. Its advisory practice puts this research to work for industries, public bodies, investors and civil society.
What we choose to count
Most transition plans rest on numbers that look settled. A product has an emission factor. Wood is carbon neutral. An efficient supply chain is a good one. A label says low-carbon.
Each of these figures depends on choices that are rarely shown: where the boundary was drawn, which method was picked among several defensible ones, what was set to zero because it was hard to count. Land that could hold carbon. Forest carbon lost at harvest. The by-product that runs out once everyone uses it. The reserve stock that looks like waste until the shock arrives.
These are not details. They decide whether a policy cuts emissions or moves them abroad, whether a material is a solution or a future liability, whether an economy absorbs a shock or breaks under it. They are also where incentives push hardest toward the convenient answer.
That is why we do fundamental research. We rebuild published models so they can be verified. We write our predictions before we run them. We carry uncertainty through to the result instead of hiding it in a single figure. We report what failed. We open code and data where we can. And we apply more scrutiny, not less, to answers that suit the person asking.
Why a laboratory also advises
Research that never meets a decision changes little. Decisions taken without research repeat the errors the numbers conceal. Industries, public bodies, investors and civil society face questions now: which technology to back, which standard to trust, which margin to keep, which use of land to favour.
So Millennia advises. Every mission draws on a research programme, and every mission returns a sharper question to it. We accept advisory work on two conditions: the method stays ours to disclose, and the conclusion stays ours to reach.
The transition will be shaped by what we choose to count. We work on counting it right.
Millennia Lab, Paris
History
- 2022A research initiative
Millennia began as a research initiative within the Engineering Division of Bouygues Immobilier, founded by Timothée de Toldi. Its aim was to bring climate adaptation, mitigation and energy sobriety into how buildings are designed and supplied, moving construction toward industrial-ecology pathways that favour natural materials.
- 2025Independence
In April 2025 Millennia became an independent company (SASU, Paris). It works with academic partners assembled for each project.
- TodayFour programmes
The lab's work now spans four questions about one transition: what it is built from, what it draws on, how it is counted and whether it holds.
People
Timothée de Toldi
Founder · Research ScientistTimothée de Toldi is a research scientist, currently affiliated with the World Resources Institute, the Center for Policy Research on Energy and the Environment (C-PREE) at Princeton University, and Millennia Lab. His work focuses on the links between material-intensive industrial systems, food systems, land use and climate change, with particular emphasis on the environmental externalities of extractive and resource-based industries.
He combines quantitative modelling with policy and public-affairs work to understand how these externalities affect climate mitigation, land-use dynamics and the robustness of societies, and to inform policies that support more sustainable and robust transitions.
Timothée founded Millennia Lab as an industrial ecology research laboratory within the Bouygues Group, then developed it into an independent spin-off. He holds an M.Sc. in Civil Engineering, with concentrations in Environmental Engineering and Climate Sciences, as well as an M.Arch. and a B.Sc., all from McGill University.
Network
Millennia works with universities and international research institutes. It contributes to a multi-stakeholder European research project on land, biomass and ocean, alongside research institutes, policymakers and other stakeholders.
Organizations we have worked with
CIR · JEIMillennia is accredited for the research tax credit (Crédit d'Impôt Recherche) and holds Jeune Entreprise Innovante status.
Working with us
We work with researchers on shared questions: co-authored papers, model reviews, data and code. If your work meets one of our programmes, write to us with the question you have in mind. We also read spontaneous applications: choose Application in the contact form.
Millennia Lab is a simplified joint-stock company (SASU) registered in Paris. Legal details are in the legal notice.