Accused of collaborating with the Germans during World War II, he died while awaiting trial in liberated France toward the end of 1944 under uncertain circumstances.

He built his first car in 1898, hiring a pair of workmen to modify a used 3⁄4 hp (560 W)[3] De Dion-Bouton cycle which featured a revolutionary universally jointed driveshaft[4] and a three-speed gearbox with reverse, with the third gear in direct drive (which he patented a year later).

On 24 December 1898, he won a bet with his friends that his invention with an innovative crankshaft could beat a car with a bicycle-like chain drive[5] up the slope of Rue Lepic in Montmartre.

Seeing the commercial potential, he teamed up with his two older brothers, Marcel and Fernand, who had business experience from working in their father's button and textiles firm.

Marcel was killed in the 1903 Paris-Madrid motor race, and in 1908, Louis Renault took overall control of the company after Fernand retired for health reasons.

During the interwar period, his right-wing opinions became well known, leading to various cases of labour unrest with proletarian avant-garde workers at the Boulogne Billancourt plant.

Louis Renault competed fiercely with Citroën, whom he called "le petit Juif" ("the little Jew"),[4][11] growing increasingly paranoid and reclusive at the same time, and deeply concerned about the rising power of Communism and labor unions, eventually retreating to his country estate, a castle on the river Seine near Rouen.

Renault remained in complete control of his company until 1942, dealing with its rapid expansion while designing several new inventions,[12] most of which are still in use today, such as hydraulic shock absorbers, the modern drum brake and compressed gas ignition.

[13] Renault was faced with the choice of cooperating with the Germans and possibly forestalling them from moving his factory and equipment to Germany, which would lead to an accusation of collaboration with the enemy.

He argued that "by continuing operations he had saved thousands of workers from being transported to Germany",[2] but, in 1942, Life described him as a "notorious Paris collaborationist".

The Renault factories on Île Seguin in Billancourt had become top priority targets for the bombers of the Royal Air Force (RAF) and were ultimately severely damaged on 3 March 1942.

Renault's health issues worsened, including his severely diminished renal function and, in late 1942, he suffered aphasia, and became unable to speak or write.

[2] When Renault's health quickly declined on 9 October 1944 he was again moved to a private nursing home at the clinic Saint-Jean-de-Dieu in the Rue Oudinot, Paris[13] at the request of his family and supporters, having gone into a coma.

[7] He died on 24 October 1944, four weeks after his incarceration, still awaiting trial and having claimed to have been mistreated in Fresnes Prison, with his 1918 French Legion of Honor, for exceptional contribution to the victory of the First World War, having been expunged by the Vichy régime.

[21] The Minister of Information, Henri Teitgen, said at the time this was not a confiscation, rather "it was merely a step to get French industry back into production.

[2] By 1956, "Renault [was] now France's largest nationalized company, employing 51,000 Frenchmen, making 200,000 automobiles and a profit of $11 million a year.

"[2] In 2005, the London Daily Telegraph reported that "according to eyewitness and family accounts, the previously wiry little 67-year-old had been tortured and beaten," and that "a nun at Fresnes testified that she saw Renault collapse after being hit over the head by a jailer wielding a helmet.

"[1] On 29 July 1967, Louis-Jean Renault, the only heir, received minor compensation, specifically for non-industrial, personal losses.

In 2011, his heirs again sought to restore Renault's reputation and receive compensation for what they see as the illegal confiscation of his company by the state.