Biography|Arthur Mensch — Three Years at DeepMind Inside 8 Rue de Londres

In November 2020 Arthur Mensch left the academic track and joined DeepMind's Paris laboratory.

The lab sat inside Google France at 8 rue de Londres, in the 9th arrondissement, a few minutes from Gare Saint-Lazare.

DeepMind had announced this first continental-European research site in March 2018. By the time Mensch arrived, the work in Paris included large language models, not only the reinforcement-learning problems the London office was known for.

He stayed about three years. The public record of that stretch is spare on internal project names, which is normal for a Google lab, and specific on the dates: in by late 2020, out in 2023.

Le Figaro later placed the start in November 2020. English and French Wikipedia both give the window as 2020 to 2023.

The building on the pin is a real office with a public street front. It is a former workplace, not a current one. He left it to incorporate Mistral AI.

What changed here was scale. The Saclay thesis had been about extracting structure from fMRI volumes. The rue de Londres years put him next to the training stacks that turn text into models large enough to ship.

When Meta released Llama in February 2023, Mensch and two polytechnicien colleagues from the Paris research circuit — Guillaume Lample and Timothée Lacroix, then at Meta — decided the same work could be done from France.

They quit that spring.

The façade a visitor sees from the pavement is the Google building. It is not a tour site. Look from the street and leave the lobby to the people who work there now.

Photo: Petit_l, CC BY 2.0, via Wikimedia Commons. Portrait: Slush, CC BY 4.0, via Wikimedia Commons