[3][4] Estienne had drawn up plans for a tracked armoured vehicle based on the Holt caterpillar tractor, and with permission from General Joffre, approached Renault as a possible manufacturer.

Renault declined, saying that his company was operating at full capacity producing war materiel and that he had no experience of tracked vehicles.

Charles-Edmond Serre, a long-time associate of Louis Renault, organized and supervised the new tank's mass production.

The FT's tracks were kept automatically under tension to prevent derailments, while a rounded tailpiece facilitated the crossing of trenches.

Because the engine had been designed to function normally under any slant, very steep slopes could be negotiated by the Renault FT without loss of power.

On 27 November 1916, Estienne sent to the French Commander in Chief a personal memorandum proposing the immediate adoption and mass manufacture of a light tank based on the specifications of the Renault prototype.

The prototype was refined during the second half of 1917, but the Renault FT remained plagued by radiator fan belt problems throughout the war.

Automitrailleuse à chenilles means "armoured car [lit: motorized machine gun] with tracks."

In Estienne's biography,[7] his granddaughter states, "It is also referred to as the FT 17: the number 17 was added after the war in history books, since it was always referred to at Renault as the FT." Lieutenant-Colonel Paul Malmassari (French tank officer and Doctor of History) states, "The Renault tank never carried the name FT 17 during the First World War, although the initials F.T.

Renault records make no distinction between 1917 and 1918 output; the decision to arm FTs with a 37mm gun was made in April 1917, before any tanks had been manufactured; because of various production difficulties and design requirements, a range of turret types were produced by several manufacturers, but they were all fitted to the basic FT body without any distinguishing reference; all FTs had the same model 18 hp engine.

Because of the wartime demands on French industry, it was decided that the quickest way to supply the American forces with sufficient armour was to manufacture the FT in the US.

The 37mm Puteaux gun was chosen, and attempts were made to produce a cast steel turret capable of accommodating it, but they were unsuccessful.

It was given the name "omnibus", since it could easily be adapted to mount either the Hotchkiss machine gun or the Puteaux 37mm with its telescopic sight.

In 1918 Forges et aciéries Paul Girod produced a successful circular turret which was mostly cast with some rolled parts.

This engagement, with 30 tanks, successfully broke up a German advance, but in the absence of infantry support, the vehicles later withdrew.

[citation needed] Estienne had initially proposed to overwhelm the enemy defences using a "swarm" of light tanks, a tactic that was eventually successfully implemented.

[22] Beginning in late 1917, the Entente allies were attempting to outproduce the Central Powers in all respects, including artillery, tanks, and chemical weapons.

[25] After the end of World War I, Renault FTs were exported to many countries (Belgium, Brazil, Czechoslovakia, Estonia, Finland, Iran, Japan, Lithuania, the Netherlands, Poland, Romania, Spain, Switzerland, Turkey, and Yugoslavia).

[26][verification needed] French tanks deployed in Vladivostok were given to the Chinese Fengtian Army of Zhang Zuolin in 1919.

[29][30] During the Rif War, after the Battle of Annual, the Spanish Army ordered 10 FT armed with Hotchkiss machine guns and 1 char TSF to supplement a first Renault bought in 1919.

The French Army deployed two battalions of FT during the war, including one company of tanks with Kégresse tracks.

[32] After the end of the war, the French tanks remained in North Africa to finish the "pacification" of Morocco in the Atlas Mountains.

Renault FT tanks were also fielded in limited numbers during World War II, in Poland, Finland, France, Greece, Romania and the Kingdom of Yugoslavia, although they were already obsolete.

Vichy France used Renault FTs against Allied invasion forces during Operation Torch in Morocco and Algeria.

The Soviet Red Army captured 14 burnt-out Renaults from White Russian forces and rebuilt them at the Krasnoye Sormovo Factory in 1920.