Centrix was a manufacturer and distributor of cycle components based in Caluire, a suburb of Lyon, France. It seems to have been established in 1925, and to still be in business in 1952. Its main products appear to have been handlebars and stems, but brakes also figure.
In about 1932 Centrix seems to have started to distribute and possibly manufacture a couple of derailleurs designed by Huret. These Centrix derailleurs were used by Alcyon and La Française Diamant (which was owned by Alcyon), both of which were prominent bicycle brands at the time. Alcyon and La Française Diamant seem to have moved on to using Super Champion derailleurs around 1936.
For the first half of the 20th century the French bicycle and bicycle components industries were dominated by companies from St-Étienne. It's noticeable that bicycle brands like Alcyon, who were from the Paris area (and therefore not from St-Étienne), were keen to use derailleurs that were also not from St-Étienne. As discussed, Centrix were from Lyon, and both Huret and Super Champion were based in gay Paris.