He was subject to violent attacks in the press and parliament for speaking out against the fighting during World War I. Pierre Brizon was born on 16 May 1878 in Franchesse, Allier, to a poor farming family.

In the legislative elections of 1906 he was a candidate in Grenoble on the platform of the Socialist Party (SFIO, Section Française de l'Internationale Ouvrière).

[2] He demanded pensions for workers, nationalization of insurance, mines, railways and progressive inheritance and income taxes.

The Confédération générale du travail (CGT, General Confederation of Labor) leaders Alphonse Merrheim, Albert Bourderon and Marie Mayoux were expected to represent France, but were refused the passports they needed to travel.

[7] On their return from Switzerland, the three deputies were the targets of a violent press campaign in which they were accused of being defeatists, traitors and spies.

He said they and he remained faithful to the old decisions of the socialist international, that if war broke out it was the duty of the working classes to try to end it quickly.

After returning to his seat as deputy, he held to his position and asked for a referendum by secret ballot on the question of war or peace.

He also asked for an inquiry into the position the government had taken regarding sending delegates to the Third Zimmerwald Conference, held in 1917 in Stockholm.

[3] In February 1917 the Committee for the Resumption of International Relations split, with Brizon, Raffin-Dugens and Bourderon joining the SFIO minority led by Jean Longuet, while the socialists Fernand Loriot, Charles Rappoport, Louise Saumoneau and François Mayoux took control of the committee.