Étienne Klein (; born 1958) is a French physicist and philosopher of science. A graduate of École Centrale Paris, he holds a DEA (Master of Advanced Studies) in theoretical physics. In June 2026, Université Paris Cité revoked his PhD in philosophy due to extensive plagiarism in his dissertation.
Profile Étienne Klein is a Research director at the Commissariat à l'énergie atomique et aux énergies alternatives (CEA).Centre Saclay CEA He is currently head of the Laboratoire des Recherches sur les Sciences de la Matière (LARSIM), a research laboratory belonging to the CEA and located in Saclay near Paris.Laboratoire des Recherches sur les Sciences de la Matière (LARSIM) He took part in several major projects, such as the adjustment of a method of isotopic separation involving the use of lasers, and the study of a particle accelerator with superconducting cavities. At CERN he was involved in the design of the Large Hadron Collider (LHC).« Carte blanche à Étienne Klein », Futura-Sciences
He taught quantum physics and particle physics at Centrale Paris for several years and currently teaches philosophy of science.« Cours d'Étienne Klein en vidéo » He is a specialist in the question of time in physics and has written a number of essays on the subject. He is also a member of the Conseil d'analyse de la société, of the conseil scientifique de la Cité des Sciences, of the Conseil de l'Office parlementaire d'évaluation des choix scientifiques et technologiques (OPECST), of the French Academy of Technologies and of the Conseil d'Orientation de l'Institut Diderot. Every Thursday morning he presents a radio chronicle, Le Monde selon Étienne Klein, as well as La Conversation scientifique every Saturday afternoon, on the French public station France Culture.« Le Monde selon Étienne Klein, 2012-2013 »
Étienne Klein practises mountain-climbing« Étienne Klein, libido sciendi, Portrait d'Étienne Klein diffusé sur universcience.tv du 22/01 au 25/02/2010.. » and other endurance sports.
Plagiarism affairs In December 2016, Science magazine, a publication of the American Association for the Advancement of Science, reported that Étienne Klein was responsible for plagiarizing the novelist Stefan Zweig and other authors.
In August 2024, French media Arrêt sur images revealed that 88 of the 429 pages of the book adapted from his PhD thesis, L’Unité de la physique (2000), contain plagiarized text by Gerald Holton, Lambros Couloubaritsis and other philosophers. After an investigation that lasted 20 months, the Université Paris Cité found Klein to have massively plagiarized in his thesis, leading to them stripping his doctorate degree and barring him from re-registering for obtaining a PhD.
Chorizo tweet
On July 22, 2022, Klein tweeted a photo that he presented as an image of Proxima Centauri, the closest star to the Solar System, taken by the James Webb Space Telescope. A few days later, he revealed that the photo was actually of a slice of chorizo against a black background. He described his tweet as a "form of amusement" and urged his 92,000 Twitter followers to "be wary of arguments from authority". Klein posted the photo a day after Peter Coles posted the same photo as a joke about JWST observations.
Distinctions and awards Officier dans l’Ordre des Palmes académiques Award for the best scientific book of the year 1993 in Germany for Conversations avec le Sphinx, les paradoxes en physique Prix Jean Perrin for popularizing science from the Société française de physique in 1997Les prix de la SFP Grammaticakis-Neumann Award from the Académie des sciences in 2000 Award for the best book of scientific literature of the year for L’Atome au pied du mur et autres nouvelles Prix Budget from the Académie des sciences morales et politiques in 2000 Prix « La science se livre » 2003 for Les Tactiques de Chronos Prix Jean Rostand in 2004 Prix Thorel for Galilée et les Indiens. Allons-nous liquider la science ? in 2008 Chevalier de la Légion d’honneur, promotion du 1er janvier 2010 Prix Thorel from the Académie des sciences morales et politiques in 2010
Bibliography Conversations avec le Sphinx, les paradoxes en physique, 1991 Regards sur la matière. Des quanta et des choses, avec Bernard d'Espagnat, 1993 Le Temps, 1995 Le Temps et sa flèche [actes du colloque], dir. Étienne Klein and Michel Spiro, 1996 L’Atome au pied du mur et autres nouvelles, 2000 L’Unité de la physique, 2000 La Quête de l’unité. L’Aventure de la physique, with Marc Lachièze-Rey, 2000 Sous l’atome, les particules La Physique quantique Trésor des sciences : dictionnaire des concepts, co-author (dir. Michel Serres) Moi, U235 noyau radioactif, with Bernard Bonin and Jean-Marc Cavedon, 2001 Le temps existe-t-il ?, Collection Les petites pommes du savoir, 2002 La science nous menace-t-elle ?, 2003 Les Tactiques de Chronos, 2003 Petit voyage dans le monde des quanta, 2004 Il était sept fois la révolution, Albert Einstein et les autres, 2005 Le Temps qui passe, 2006 Le facteur temps ne sonne jamais deux fois, 2007 Les Secrets de la matière, 2008 Galilée et les Indiens. Allons-nous liquider la science ?, 2008 Pourquoi je suis devenu chercheur scientifique, 2009 Discours sur l’origine de l’univers, 2010 La Science en jeu, written with Jean-Michel Besnier, Hervé Le Guyader and Heinz Wismann, 2010 Le Small bang des nanotechnologies, 2011 Anagrammes renversantes, ou le sens caché du monde, with Jacques Perry-Salkow, 2011 Rugby quantique, with Jonny Wilkinson and Jean Illiopoulos, 2011 D'où viennent les idées (scientifiques)?, 2013 En cherchant Majorana. Le physicien absolu, 02/2015 Y a-t-il eu un instant zéro ?, 03/2015 Le pays qu'habitait Albert Einstein, 2016 Tout n'est pas relatif, 2017 Sauvons le progrès, dialogue avec Denis Lafay, 2017 Matière à contredire, essai de philo-physique, 2018 Le goût du vrai, 2020
Filmography Quels temps font-ils ?, co-author with Marc Lachièze-Rey, film directed by Hervé Lièvre, 2001
References