In 1845, Marc Secretan (1804–1867), a Swiss mathematician, and Noël Paymal Lerebours (1807–1873), a French optician, established a firm in Paris that manufactured precision instruments.

With popular interest in astronomy growing, the French physicist Léon Foucault (1819–1868) entered into an exclusive contract with Secretan for the commercialization of a reflecting telescope.

Around 1889, Georges Secrétan moved the company’s workshops to 30 rue du Faubourg Saint-Jacques, near the Paris Observatory and appointed Raymond Augustin Mailhat (1862 – 1923) as their head from 1 January 1889.

In 1894, Mailhat bought some of the workshops and set up his own business, while Secretan moved his equipment into a new location at 41, quai de l’Horloge, near to the company’s retail shop on the Place du Pont-Neuf.

In 1913, Gustave Jacquelin (1879–1939) became Épry’s associate and the firm continued manufacturing and selling astronomical, scientific and optical products.