[3] The violent personal attacks in a pamphlet entitled Marie-Joseph Chénier et le prince des critiques (1844), in reply to Jules Janin led the later to successfully sue him for libel earning Pyat a six months' sojourn in the Sainte-Pélagie prison, in the cell just vacated by Lamennais, along with being considered a minor political "martyr" of the July Monarchy.

He joined Ledru-Rollin in the attempted insurrection of 13 June 1849, after which he sought refuge in Switzerland, Belgium, and finally in England,[8] where he became involved with the irregular masonic organisation, La Grande Loge des Philadelphes.

[citation needed] For having glorified regicide after Orsini's attempt on the life of Napoleon III he was brought before an English court, but acquitted, and the general amnesty of 1869 permitted his return to France.

[9] The deposing of Napoleon III on 4 September 1870 brought him back to Paris, and it was he who in his paper Le Combat displayed a black-edged announcement of the negotiations for the surrender of Metz to the Prussians.

He was superseded on the committee by Delescluze, but he continued to direct some of the violent acts of the Commune, the overthrow of the Vendôme column, the destruction of Adolphe Thiers's residence and of the expiatory chapel built to the memory of Louis XVI.