Clément-Bayard, also known as Bayard-Clément,[1] was a French manufacturer of automobiles, aeroplanes and airships founded in 1903 by entrepreneur Gustave Adolphe Clément.

[2][4][5] From 1903 Clément-Bayard automobiles were built in a modern factory at Mézières, known as La Macérienne, which Clément had designed in 1894 mainly for building bicycles.

The company entered the field of aviation in 1908, announcing the construction of Louis Capazza's 'planeur', a lenticular airship, in L'Aérophile in May 1908.:[6] however it was never built.

Adolphe Clément also built Alberto Santos-Dumont's Demoiselle No 19 monoplane that he had designed to compete for the Coupe d'Aviation Ernest Archdeacon prize from the Aéro-Club de France.

[2][4][5] In 1896 Adolphe Clément who held the extremely profitable manufacturing rights for Dunlop tyres in France joined with a syndicate led by Dunlop's founder Harvey Du Cros to buy out the Gladiator Cycle Company and they merged it into a major bicycle manufacturing conglomerate of Clément, Gladiator & Humber & Co Limited.

[7] In 1910 Clément-Bayard started to manufacture a stylish, low cost, small, two-seater roadster, with a 4-cylinder 10/12 hp, and a heater for the driver and passenger.

[10][11][12] Albert Clément finished 10th at the I Eliminatoires Françaises de la Coupe Internationale, held at the Forest of Argonne on 20 May 1904.

This was an eliminating contest for the French entry into the Coupe Internationale (Gordon Bennett Race) where only three cars were allowed per country.

[10] Albert Clément retired his Clement-Bayard with overheating after 1 lap of the II Eliminatoires Françaises de la Coupe Internationale at the Auvergne on 16 June.

Clement's team-mate Rene Hanriot finished tenth in 8 hours 23 minutes 39.6s but failed to qualify, whilst Marc-Philippe Villemain retired after three laps.

[11] At the 1905 Vanderbilt cup on Long Island Clément drove an 80 hp Clément-Bayard (France #12) but suffered reliability problems.

[11] Clément-Bayard entered 3 cars for the inaugural 1906 French Grand Prix at Le Mans where Clément finished third in his 100Hp machine.

[12] At the 1906 Vanderbilt cup Clément finished 4th driving a 100 hp (75 kW) Clément-Bayard (France #15) and completing the ten laps averaging 59.0 mph (95.0 km/h).

[2] The company entered 3 cars for the 1908 French Grand Prix which had 13,963 cc (155 x 185 mm) 4-cylinder overhead camshaft,[16] and Victor Rigal finished 4th.

[7] The company also started working with Alberto Santos-Dumont in 1908 to build his Demoiselle No 19 monoplane that he had designed to compete for the Coupe d'Aviation Ernest Archdeacon prize from the Aéro-Club de France.

[7] Jean Chassagne who was working on the development and testing, participating successfully in variety of early aviation challenges winning endurance, altitude and speed prizes.

The Clément-Bayard No.1 airship was offered to the French government but was too expensive so it was bought by Tsar Nicholas II for the Russian army.

[2][7] Adolphe Clément ceded control of Clément-Bayard to his son Maurice in early 1914, but the consequences of World War I for the company were disastrous.

The La Macérienne factory at Mézières was lost to the Germans, the machinery was shipped back to Germany, and the forges, foundries and smelter were destroyed.

[7] In 1922 the Clément-Bayard automobile company was sold to André Citroën, in whom Adolphe Clément also invested financially, and the factory at Levallois-Perret became the centre of 2CV manufacturing for the next 40 years.