At the heart of the French National Assembly, a restoration project has sparked a multidisciplinary scientific adventure centered around the work of Eugène Delacroix.
Taking advantage of the library’s restoration, art historian Barthélémy Jobert and his team launched the Delacroix Numérique project: 3D modeling, artificial intelligence, and art history come together to reveal the secrets of a landmark 19th-century décor. A highlight of this collaboration came on April 8, 2025, when Sorbonne University and the French National Assembly signed an institutional partnership agreement, sealing their shared commitment to research and heritage preservation.
A Restoration Project at the Heart of the National Assembly
The French National Assembly is home to two decorative ensembles painted by Eugène Delacroix and his assistants. The first, restored thirty years ago, is located in the Salon Delacroix, adjacent to the chamber. But it is the ceiling of the library that presents the greatest artistic and technical complexity. Spanning approximately fifty meters in length and twenty meters in width, the décor features five domes, each divided into four sections and adorned with architectural and sculptural elements, all framed by two hemicycles. The entire ensemble rises to a height of about twenty meters.
In the summer of 2023, the National Assembly decided to restore the library from floor to ceiling. This restoration involved the installation of scaffolding—providing a unique opportunity to launch a photographic campaign of the library ceiling, thus making possible the research project long envisioned by art historian and Delacroix specialist Barthélémy Jobert. “During various restorations of Delacroix’s mural decorations that I had participated in, I had the chance to observe the artist’s work up close. I had always kept in mind the idea of offering the general public a virtual visit that would bring them as close as possible to these décors. Very quickly, the concept of this digital tour evolved into a more ambitious project: conducting an in-depth analysis of Delacroix’s works. The goal, then, was to carry out a photographic campaign with extremely high-resolution images capable of capturing both the material qualities of the artworks and their spatial arrangement,” explains the researcher.
The restoration of the library and the installation of scaffolding thus became the catalyst for these long-gestating initiatives.
A Unique Scientific Documentation on Delacroix
“During the restoration project, the National Assembly demonstrated exemplary cooperation,” notes Barthélémy Jobert. “We were able to carry out the equivalent of three photographic campaigns—before, during, and after the restoration—thanks to the invaluable support of a visual studies engineer from SCAI, who handled all the image capture following the cleaning of the paintings and after the actual restoration work.”
Thanks to the more than 10,000 images collected during the campaign, scientific visualization engineer Nicolas Leys has already produced a two-minute digital model that allows users to virtually navigate through the space. “The quality is so high that the restorers, by zooming in on certain details, were able to see elements invisible to the naked eye. We now have an exceptional documentary base, which is finally allowing us to move forward with the lines of research we had long envisioned around Delacroix.”
Four Pillars for an Ambitious Program
The Delacroix Numérique project is currently unfolding around four main axes. Two of them are directly linked to the décor of the National Assembly library. The first involves the creation of a high-quality virtual tour allowing the public to freely explore the décor through a web interface. “We want to offer a fully immersive experience, where users choose their own path, with the ability to zoom in on the finest details—even down to surface textures. This presents technical challenges, such as collecting and processing a massive amount of data, but also making it accessible with reasonable loading times,” explains Barthélémy Jobert.
The second focus is the scientific analysis of the library ceiling’s decoration. This is where artificial intelligence (AI) comes into play. “We believe it is possible—even if still experimental—to analyze the décor as a whole and identify which sections were painted by Delacroix himself, and which were completed by his assistants. The goal is to train an AI to distinguish between these different artistic hands,” summarizes the specialist.
Researchers benefit from two key assets: on one hand, the exceptionally high quality of the data collected during the library’s restoration; on the other, a partnership with the C2RMF (Centre for Research and Restoration of the Museums of France), which will provide photographic documentation of Delacroix’s works. “This will allow us to enrich our training dataset and improve our chances of achieving reliable results that highlight Delacroix’s unique painterly signature,” adds Barthélémy Jobert.
A third axis, initiated several years ago, concerns Delacroix’s correspondence. “With the evolution of digital humanities over the past fifteen years, our approach has shifted,” says the art historian. What was initially a project to publish the correspondence online has now become a foundation for the intellectual analysis of the painter’s work through text mining—exploring ideas, concepts, links with 19th-century art criticism, and cross-referencing with Delacroix’s contemporaneous writings.
Finally, a fourth axis—long considered hypothetical—is now becoming feasible. It involves using generative AI to digitally reconstruct the décor lost during the 1871 fire of the Salon de la Paix, painted by Delacroix at Paris’s City Hall. All that remains are sketches, preparatory drawings, a few copies made by his students, and two old photographs. These are complemented by period architectural plans, measurements, and documentation on a second salon painted by Ingres.
“With these materials, and the help of video game specialists, we can virtually reconstruct the architecture of the space,” the researcher hopes. Generative AI, informed by interpretive data from the previous project and Delacroix’s preparatory work, could then produce a credible reconstruction of the lost frescoes. “Even though we now have the best database possible, AI is not absolute truth. It provides probabilities, not certainties. It’s up to us—art historians and scientists—to interpret the results,” Barthélémy Jobert reminds us.
A Multidisciplinary Effort
So far, the project has progressed thanks to the commitment of several teams from Sorbonne University across various faculties: the André-Chastel Center for the art history component; the Plemo 3D platform, which scanned the library and the Salon Delacroix at the National Assembly a few years ago, along with Delacroix’s religious décors in the Parisian churches of Saint-Sulpice and Saint-Denys du Saint-Sacrement; SCAI for the photographic campaign and AI aspects; the ObTIC platform for digital analysis of the correspondence; and the LAMS (Laboratory of Molecular and Structural Archaeology), specializing in the chemical analysis of art materials, which will help differentiate between Delacroix’s work and that of his assistants. “The LAMS assembled a team that conducted non-invasive analyses using optical techniques to gather data on pigments and materials. While limited to selected zones, this data is valuable and will complement that of the C2RMF,” says the art historian.
While over three-quarters of the project has been carried out using internal resources at Sorbonne University, since March 2025, the project has received a major boost from the Schmidt Foundation, which funds initiatives combining AI and cultural heritage. “Our project was selected, and we received funding to hire a scientific visualization engineer and allocate time for a data scientist dedicated to identifying the authors of the various parts of the décor.” The Schmidt Foundation is also enabling the recruitment of a postdoctoral AI researcher, who will work alongside the data scientists, scientific visualization interns, and a postdoctoral art historian. The latter will focus on two areas: calibrating the images provided by the C2RMF, and analyzing textual corpora.
Another potential source of funding may also be added: “We’ve applied to Sorbonne University’s ‘Pre-Maturation’ grant to bring in interns from the video game sector and hire a cultural mediation engineer to develop a first version of the virtual tour.” This tour is expected to be available to the public within six months to a year, on both the National Assembly and Sorbonne University websites.
Project Outlook
“With this funding, we are now able to accelerate progress across all areas of the project,” announces Barthélémy Jobert. With a start date scheduled for September, researchers hope that within a year, they will be able to draw conclusions from the project’s two most experimental components: the digital reconstruction of the Salon de la Paix and the analysis of the “hands” behind the library décor.
Barthélémy Jobert also envisions expanding the project: “In the short term, we could respond to calls for proposals to extend the study to other restored Delacroix décors, or even intervene upstream of the upcoming restoration of the Senate Library.” In the longer term, the researchers are considering broadening the scope of the study to other major 19th-century French mural decorations beyond Delacroix—or more generally, to large-format painting from the same period.