The Schneider CA 1 (originally named the Schneider CA) was the first French tank, developed during the First World War.

The Schneider was inspired by the need to overcome the stalemate of trench warfare which on the Western Front prevailed during most of the Great War. It was designed specifically to open passages for the infantry through barbed wire and then to suppress German machine gun nests. After a first concept by Jacques Quellennec devised in November 1914, the type was developed from May 1915 onwards by engineer Eugène Brillié, paralleling British development of tanks the same year. Colonel Jean Baptiste Eugène Estienne in December 1915 began to urge for the formation of French armoured units, leading to an order in February 1916 for four hundred Schneider CA tanks, which were manufactured by SOMUA, a subsidiary of Schneider located in a suburb of Paris, between September 1916 and August 1918.

Like most early tanks, the Schneider was built like a simple armoured box, without compartmentalisation of the inner space. It lacked a turret, with the main armament, a short 75 mm cannon, in a sponson on the right side. By later standards it would therefore have been an assault gun instead of a tank. The vehicle was considered a very imperfect design, because of a poor layout, insufficient firepower, a cramped interior and inferior mobility due to an overhanging nose section, which had been designed to crush through the belts of barbed wire but in practice caused the tank to get stuck. Improved designs were almost immediately initiated but the production of these, the Schneider CA 2, CA 3 and CA 4, was eventually cancelled.

The Schneider CA 1 tanks were widely used in combat during the last war years. Their first action on 16 April 1917 was largely a failure, the tank units suffering heavy losses, but later engagements were more successful. In 1918 the Schneider tanks played an important role in halting the German spring offensive and breaking the German front in the French summer offensives. They were active until the end of September 1918, less than two months before the Armistice of 11 November 1918, their numbers having dropped considerably due to attrition. After the war the surviving tanks were mostly rebuilt as utility vehicles but six Schneider tanks were deployed by Spain in the Rif War in Morocco and the type saw its last action in the beginning of the Spanish Civil War.

Before the First World War, mechanic Charles Marius Fouché cooperated with engineer Édouard Quellennec and the latter's son Jacques Quellennec to adapt existing caterpillar tractors to the conditions of Egyptian and French farming, among them the Holt Model 75. In this context in 1914 contacts were made with engineer Eugène Brillié of Schneider & Co. to adapt the Castéran Flexible Track Tractor. When that year war broke out, Jacques Quellennec was drafted as an infantry sergeant, witnessed most men of his unit being slaughtered during the First Battle of the Marne and was then severely wounded at the end of October. While recovering, he devised plans for an armoured tractor armed with a machine-gun and capable of destroying German machine-gun nests. Many in this period had comparable ideas but contrary to most, Quellennec had excellent contacts. Fouché had become a second lieutenant with the Grand Parc Automobile de Réserve of the Service Automobile, the Army branch responsible for motorisation, and Brillié was chief designer with one of France's main arms manufacturers. Early December, Quellennec met Fouché in Paris and both then went to Brillié to present drawings of a tracked armoured fighting vehicle. During a second visit Quellennec urged Brillié to bring over two Holt Model 75 tractors, at that time present in Tunisia, to France in order to perform the first trials. Brillié showed himself less than enthusiastic about the idea, objecting there would be not enough room on a tractor for both crew and armament. In February 1915, Quellennec was sent to an air force training base and tasked Fouché with trying to convince Brillié, without much apparent success.

Meanwhile, the Schneider company had been given the order to develop heavy artillery tractors in January 1915. On 30 January it sent out its chief designer, Brillié, to investigate tracked tractors from the American Holt Company, at that time participating in a test programme at Aldershot in England. On his return, Brillié, who had earlier been involved in designing armoured cars for Spain, apparently without mentioning being influenced in this by Quellennec, convinced the company management to initiate studies on the development of an armoured fighting vehicle, based on the Baby Holt chassis, two of which were ordered. The type was intended to be sold to the French Cavalry.

Experiments on the Holt caterpillar tracks started in May 1915 at the Schneider plant with a 75 hp wheel-directed model and the 45 hp integral caterpillar Baby Holt, showing the superiority of the latter. The Castéran and the Killen-Strait Tractor were also tested but rejected. Work was now begun on an auto-mitrailleuse blindée à chenilles ("tracked armoured self-propelled machine gun"). On 16 June, new experiments followed in front of the President of the Republic Raymond Poincaré, leading to the order of six, later expanded to ten, armoured tracked vehicles for further testing. The type was since July called a machine offensive à chenilles ("tracked offensive machine") and was based on the Baby Holt with a suspension that was to be thirty centimetres lengthened. In August drawings were made of what was now designated the tracteur blindé et armé ("armoured and armed tractor"). In September 1915 the Schneider programme was combined with an official one for the development of an armoured barbed wire cutter by engineer and Member of Parliament Jules-Louis Breton, the Breton-Prétot machine. Ten of the fifteen available Baby Holt vehicles were to be armoured and fitted with the wire cutter of which ten systems had been ordered on 7 August. This involved the Service Automobile in the project. On 10 September, new experiments were made for Commandant L. Ferrus, an officer who had been involved in the study (and ultimate rejection) of the Levavasseur tank project in 1908.

On 9 December 1915 in the Souain experiment, a Schneider prototype armoured tank, a Baby Holt chassis with boiler-plate armour, was demonstrated to the French Army. Among the onlookers were General Philippe Pétain, and Colonel Jean Baptiste Eugène Estienne — an artillery man and engineer held in very high regard throughout the army for his unmatched technological and tactical expertise. The results of the prototype tank were, at least according to Estienne, excellent, displaying remarkable mobility in the difficult terrain of the former battlefield of Souain. The length of the Baby Holt however appeared to be too short to bridge German trenches, justifying the development of longer caterpillar tracks for the French tank project. For Estienne the vehicle shown embodied concepts about armoured fighting vehicles which he had been advocating since August 1914. Already on 1 December Estienne had proposed to the French GHQ the use of tracked armoured tractors to move infantry, equipment and cannon over the battlefield, having performed some trials with British caterpillar tractors. On 11 December Estienne let a certain lieutenant Thibier draw a sketch of two conceptions: the one of a Baby Holt chassis fitted at the front and the back with auxiliary rollers, to improve the trench-crossing capacity; the other of an elongated suspension protected by side armour.