[3] On his return Métin wrote Le socialisme sans doctrines: la question agraire et la question ouvrière en Australie et Nouvelle-Zélande in which he described "these countries in which the state has set limits to the right of property, has instituted the eight-hour day, the minimum wage, compulsory arbitration, with many other measures which have given the English antipodean colonies the surname Paradise of Workingmen.

In the period before World War I (1914–18) he was a member of commissions on social security, civil pensions, fiscal legislation, the budget and foreign affairs.

On 9 December 1913 Gaston Doumergue appointed him Minister of Labor and Social Security, a position he held until 3 June 1914.

[1] He was supported by the journal le Petit Comtois, which in January 1914 reported his work to give workers access to low-cost housing, to improve old age pensions, particularly for women and widows, to obtain disability pensions and to provide insurance against agricultural accidents.

[1] On 27 July 1917 Denys Cochin submitted his resignation as sub-secretary of state for Foreign Affairs, largely due to frustration over difficulties in achieving a full blockade of Germany and her allies.

Metin took his place, holding office until Clemenceau created a blockade ministry under Charles-Célestin Jonnart on 17 November 1917.

[10] Métin died on 16 August 1918 in San Francisco of apoplexy, thought to have been caused by the strain of his work on the mission.