Lse. Montandon-Lütz et Fils was a maker of balance springs in Geneva in the late 19th century. It claimed to be descended from the firm of Jean-Célanis Lutz, which originated the mass production of hardened balance springs, but that legacy and brand was also claimed by the company of Charles Dufaux. It was liquidated rather than joining the 1895 cartel to corner the production of these springs, Société des Fabriques de Spiraux Réunies (FSR).
The company was likely run by Adolphe Montandon-Lütz and his brother Jean. After his death (by 1883), his widow Louise Lütz took over management. At this time the company moved to Rue de Montblanc 42, the same address used by George Sandoz (Páquet and Rivenc), a former competitor in the business. It is likely that the companies were effectively merged.
Although Montandon-Lütz was successful for a time, the firm was not competitive with the mass produced springs of Baehni in Bienne, Sandoz in Geneva, or the high-end springs of C.-A. Paillard, and had lost the Lutz name to Charles Dufaux' company. Thus, Montandon-Lütz was left out of the establishment of Fabriques de Spiraux Réunies (FSR) in 1895. It is likely that the cartel purchased the company and shut it down.
- 1871 - Gentil-Lutz is listed at Servette 433 in Geneva
- 1877 - Montandon-Gentil-Lutz is listed at Servette 433 in Geneva
- 1878 - L. Montandon-Lütz & Cie, maker of balance springs, receives a silver medal at the Universal Exposition in Paris
- 1880 - L. Montandon-Lutz & Fils advertises itself as successor to J.-C. Lutz & Fils and is located at Chantepoulet 9 in Geneva as a maker of hardened steel balance springs
- 1880 - L. Montandon-Lutz & Cie wins a first-class bronze medal at the Bienne exposition alongside Baehni and F. Bernard
- 1881 - Montandon-Lutz wins a second class bronze medal at the La Chaux-de-Fonds exposition alongside Rivenc-Paquet & Sandoz and Baehni Frères but behind C.-A. Paillard
- 1882 - L. Montandon-Lutz & Fils wins a first prize at the Universal Exposition in Melbourne
- 1883 - A business survey shows Louise Lütz, widow of Adolphe Montandon, and Jean Charles Adolphe Montandon, both of Le Locle and Brévine, as managers of Lse. Montandon-Lütz & Fils, a maker of balance springs at Rue Montrbillant 42 in Geneva; this is the same address used by Sandoz Spiraux, successor to the former Páquet and Rivenc
- 1892 - Jean Montandon-Lütz is involved in the Syndicate des Fabricants de Spiraux, a predecessor to FSR, alongside Baehni, George Sandoz, Charles Dufaux, and F. Guye & Cie
- 1887 - Montandon-Lütz is mentioned alongside Dufaux Lutz, Baehni, and G. Sandoz in an article responding to allegations of price fixing
- 1895 - The company Lse. Montandon-Lütz & Fils is liquidated and deleted, likely as a result of a buyout by FSR