It was founded to serve the rapidly growing market for electrical power transmission and for telegraph and telephone cables.

He developed a bronze alloy that combined the conductivity of copper with the strength to remain stretched between poles 50 metres (160 ft) apart, of great value to telegraph and telephone companies, and obtained several patents in France and other countries.

Weiller remained interested in research and explored transmission of images over electrical wires, colour photography and flying.

It included forges, foundries, rolling mills and wireworks and processed copper, steel, aluminum, brass, bronze and nickel.

In 1911 TLH further increased its production of electrical wires and cables by merging with the Canalisation électrique company, giving it a dominant position in the industry, reducing competition and opening new markets in Paris streetcars, the PTT and other ministries, railways and so on.

Examples were Henri Cahen, director of the Société des applications industrielles; Alphonse Hauser, retired chief engineer of the navy and administrator of the Compagnie des ports de Tunis, Sousse et Sfax; Raymond Jarry, administrator of the Société des hauts fourneaux de la Chiers; Gaston de La Mathe, administrator of the Société Éclairage électrique and Société Énergie du nord de la France; and René Robard, an engineer also on the board of Alluminio italiano.

[4] In the spring of 1917 five workers were dismissed for circulating a petition that objected to downgrading the classification of some jobs and demanded a cost of living allowance.

TLH tried but failed to acquire the Société électrométallurgique française de Froges, the largest French producer of aluminum.

TLH did manage to acquire a large stake in the Société d'Alais et de la Camargue, an aluminum producer.

Although TLH did not gained as large a share of aluminum as they wanted in France, the company expanded its interests in this metal in Norway and Italy.

The plant made wire, tubes and sheets of copper and steel which were then shipped to the mechanical construction and electrical industries.

[13] A 1952 study said Trefileries et Laminoirs du Havre had a capital of 3,132 million francs and holdings in Hauts Fourneaux de la Chiers, Alais-Froges, Financiere Metallurgique Electrique, Lignes Telegraphiques et Telephoniques, Etablissements Bouchery, Signaux et Entreprises Electriques, Etablissements Coquillard and the Societe Procol.

In 1969 Chiers-Châtillon merged with Cousin frères to form the Société Seine et Lys, which closed in 1972, laying off 425 people.

[21] Between 1980 and 1987 the Tréfimétaux subsidiary reduced staff from 6,000 to 2,500 and closed the factories in Le Havre and Dives sur Mer.

[21] In 1986 Tecnor, manufacturing wire cables and conductors, took an area of 158,000 square metres (1,700,000 sq ft) of the La Havre factories, of which 74,000 square metres (800,000 sq ft) were covered, with a line of casting, continuous rolling and wire drawing machines.