Sizaire Frères et Naudin was a French

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 automobile

Automobile

An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

 manufacturer based in Paris between 1905 and 1921.

Sizaire-Naudin was founded by Maurice (1877-1970) and Georges Sizaire (1880-1924) and Louis Naudin (1876-1913) in around 1900. The company was registered in 1903. The partners had experimented with a car in 1902 or 1903 but it was not until 1905 that the first ones were offered for sale and shown at the Paris Salon in that year.

The first cars were basic single cylinder

Cylinder (engine)

A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

 vehicles with independent front suspension by sliding pillars and a transverse leaf spring

Leaf spring

Originally called laminated or carriage spring, a leaf spring is a simple form of spring, commonly used for the suspension in wheeled vehicles...

, identical to earlier Decauville

Decauville

The Decauville manufacturing company was founded by Paul Decauville , a French pioneer in industrial railways. Decauville's major innovation was the use of ready-made sections of light, narrow gauge track fastened to steel sleepers; this track was portable and could be disassembled and transported...

s. A unique gearbox used an integral 3 speed differential - 3 straight cut pinions brought to bear in turn on a single large straight cut crown wheel.

Orders were good and the company received backing to move to larger premises from bicycle importers Hammond et Monnier who soon afterwards sold the firm to the Duc d'Uzes and from 1907 the family crest appeared on the radiator surround.

They enjoyed great success in early voiturette

Voiturette

Voiturette is a word mostly used to describe a miniature automobile; however, it has several nuanced meanings, depending largely on the usage date.-History:...

 races with rules which limited cylinder bore but did not specify stroke length. This success lasted from 1906 to 1909, with some presence in racing until 1911.

By 1911 the single cylinder format was outmoded, and an attempt to fit a four cylinder 1847 cc Ballot

Ballot (automobile)

Ballot was a French automobile manufacturer who made cars between 1921 and 1932.The Ballot brothers, Edouard and Maurice, founded their company in 1905. Before World War I they manufactured automobile and marine engines. The company was re-founded as Etablissements Ballot SA in 1910.Edouard...

 engines did not result in significantly increased sales.

After World War I production restarted with a new company, Société des Nouveaux Établissements Sizaire et Naudin, making Ballot-engined cars based on prewar designs. In spite of an attempt to re-enter racing at the International Voiturette Cup of 1921 the directors called in the liquidators later in the year.

The Sizaire brothers left the company in 1912 and founded Sizaire-Berwick.