He escaped arrest by the Gestapo, made his way to England, and represented the trade union movement in General de Gaulle's Free French government.

His grandfather, Augustin Gazier (1844–1922) was a professor of literature at the Sorbonne who headed the Association of Friends of Port-Royal-des-Champs.

His father taught literature at the Lycée de Valenciennes, and was co-editor of a major edition of the works of Pascal.

[3] At the age of 20 Gazier obtained a job on 31 May 1928 with the bookstore of the Presses Universitaires de France in the Latin Quarter of Paris.

[4] Gazier joined the General Confederation of Labour (Confédération générale du travail, CGT) in 1930.

[5] He created a section for book salespeople within the Union of Employees of the Paris Region (Chambre syndicale des Employés de la région parisienne), a union affiliated with the Federation of Employees (Fédération des Employés) headed by Oreste Capocci.

In September 1935, Gazier was elected secretary-general of the Union of Employees of the Paris Region, while continuing to work as a bookseller.

[9] He was associated with Léon Jouhaux's group in the CGT and condemned the Molotov–Ribbentrop Pact between the Soviet Union and Germany in August 1939.

[10] At the outbreak of World War II in September 1939 Gazier enlisted voluntarily, despite having been exempted from military service in 1928.

[9] Gazier's union continued to try to support workers, prevent layoffs and obtain wage increases.

He waited in a cow shelter near the village of Villevieux until the British airplane landed in a small field guarded by Resistance members, then flew to England with twelve other passengers.

[11] Gazier went on from London to Algiers, where he represented the CGT in the Provisional Consultative Assembly convened by General Charles de Gaulle.

[9] The CGT and Christian democratic union delegates helped defuse tensions between resisters and politicians in the Assembly.

Glazier observed that, "For the first time in the history of the labor movement trade unionists took part in their own right in a political assembly.

[10] At the London conference in February 1945 he argued unsuccessfully for separation of political and union offices on the basis that they were incompatible.

[18] During the Suez Crisis, in October 1956 Gazier was in charge of the Quai d'Orsay while Christian Pineau, the Minister of Foreign Affairs, was in New York.

On 14 October 1936 he flew to London with General Maurice Challe to meet Prime Minister Anthony Eden.

[20] Eden told Gazier and Challe he would ask the Iraqis to hold back from moving troops to Jordan.

[22] Eden's acceptance of this plan led to the fall of his government and the end of British authority in the Middle East.

[13] After leaving the chamber Gazier joined a socialist advisory group as head of its department of Third World cooperation.

[25] The analysis covered the reasons for under-development, the different problems that these countries experienced, and finally the different solutions that he considered feasible.

He noted that in the French African colonies many goods were sold at much higher prices than were charged in metropolitan France, typically at 50% more.

He said it was certain that the prophecies of Karl Marx would come true if socialist and unionist actions did not put an end to the absolute poverty of the workers.

In 1983 François Mitterrand appointed him to the High Council of the Judiciary (Conseil supérieur de la magistrature).