Le Gui was a small Paris-area carmaker, active from about 1904 to 1916.
It was run by two successive firms, both in Courbevoie, Seine: H. Guillemin et Cie (1904–1909) and E. Nicolas et Cie (1909–1916). The second firm is the “E. Nicolas & Cie, Constructeurs” named on the ad below, at 8–12 rue de Metz.
The make was sold as both “Le Gui” and “Guy”.
In the early years the two names were used indiscriminately, and in England the car was also known as the Millard-Le Gui, after one of the importers who handled it. Another British importer was W. J. Mayer and Co of Chiswick.
The first models had shaft drive, round radiators, and a short-lived 7hp air-cooled four, which gave way to 9hp and 11hp voiturettes; the 9hp used a 942cc Buchet engine. A 1.3-litre 4-cylinder Le Gui ran in the 1908 Coupe des Voiturettes.
By 1908 there was a wide range of four-cylinder cars in 1.8, 2, 3.1, and 5.5 litres, mostly with proprietary engines. The largest had chain drive.
After 1909 the firm under Nicolas focused on small cars with L-head four-cylinder engines and four-speed gearboxes. A 1.6-litre Guy Ten sold for £250 in England in 1910. Later cars used Chapuis-Dornier engines, including a very long-stroke (85x160mm) 3.6-litre four.
(sources: Prewar, The Society of Automobile Historians, Wikipedia)