In July 1920, he returned to work for transportation companies as a tax collector; over the subsequent months, he continued to organise within the rail workers' unions.

The revolutionary minority, including the CSR, was subsequently expelled from the CGT and founded the United General Confederation of Labour (CGTU).

At the June 1922 congress of the CGTU, Monmousseau's motion to join the RILU passed and Besnard's attempts to resist their affiliation with the French Communist Party (PCF) were defeated.

[1] In November 1924, the revolutionary syndicalist minority held a congress to determine its course of action, culminating in the establishment of the Union fédérative des syndicats autonomes (UFSA).

Besnard opposed the entry of the Confederación Nacional del Trabajo (CNT) into the Spanish government, warning it against "deviations" from anarcho-syndicalist principles.

In order to distribute it within Vichy France, Besnard criticised Nazi Germany and Fascist Italy, but withheld criticism of the collaborationist regime.

At this time, he was discovered to have joined the Legion of French Volunteers Against Bolshevism, which he justified as an attempt to halt the dictatorship's repression of the anarcho-syndicalists.

[1] In March 1945, Besnard and other anarcho-syndicalists established the Fédération syndicaliste française (FSF), which organised the revolutionary minority within the CGT.

The following year, in May 1946, Besnard participated in an FSF congress, where it was decided to break away from the CGT and establish a separate trade union centre.

In December 1946, Besnard co-founded the Confédération Nationale du Travail (CNT), wrote its charter and was elected to head its publication Combat syndicaliste.