[1] He joined the Communist Party of the Russian Federation (PCF) for two years and sold L'Humanité by auction, which led to other fights with the opposing camp.

[9] Henri Leclerc has defended famous clients, such as the newspaper Libération,[10] the mathematician Alexandre Grothendieck, Richard Roman, Lucien Léger,[4] Charlie Bauer,[4] Michel Vaujour,[4] François Besse,[4] Roger Knobelspiess,[4] Florence Rey, Doctor Archambeau, Hélène Castel, Jacques Viguier, Véronique Courjault, Dominique de Villepin,[11] Dominique Strauss-Kahn (in the case that opposed him to Tristane Banon[12] then in the so-called Carlton case in Lille[13]) and Alain Lipietz, who was convicted of defamation.

[14] During the Jacques Tillier-Jacques Mesrine case in September 1979, the former having been left for dead at the bottom of a mushroom cellar, he defended one of the suspects, Charlie Bauer, who since 1977 has been granted parole, found a job as a bookseller and started a family.

He discovers that his wife Renée Gindrat's account was checked as early as September two days before the identikit portrait inspired to the victim by a photo of Charlie Bauer and then questions Commissioner Mireille Ballestrazzi, who does not know why the OCRB did the financial research of September 13, which will allow her to obtain Bauer's acquittal at the trial in 1982, even if he is convicted of cannabis trafficking and receiving stolen property from part of a ransom from another kidnapping.

He also acted as a civil party in the Omar Raddad case (representing the family of Ghislaine Marchal), represented the family of Pierre Overney, and defended the ex-boxer Christophe Dettinger, accused of intentional violence against police officers.

[1] Patrick Beaudouin, president of the French League of Human Rights, said: "At this moment, with sadness and with the feeling of a great emptiness...

The documentary series Footprints of France 5 dedicated an issue to him, Henri Leclerc, in the name of the man, a 52-minute film written and directed by Rémi Lainé and co-produced by France 5 / Campagne Première/ INA; production déléguée Carole Bienaimé ; broadcast on 28 September 2008.