Tiré à part du site http://www.watchfinder.co.uk/cartier-watches.aspx :
"The early mens wristwatches were all handmade in France, with movements by Jaeger, Cartier Paris and the European Watch and Clock Co, who manufactured complicated movements such as chronographs, minute repeaters, and digital wristwatches.
Ladies wristwatches became popular more quickly as the pocket or fob watch were not as comfortable to wear for women. During the Late 1920's and early 1930's ladies wristwatches began to get smaller and smaller. The smallest was a 2-line movement manufactured by the European Watch and Clock Company and Jaeger.
The ability to create many unique wristwatches was of great advantage to Cartier because customers were able to select from various designs, or order custom made pieces. Because the shops only sold their own brand they had no competition from other competitors in store.
Cartier wristwatches were produced with movements by Jaeger, Vacheron, Le Coutre, Cartier itself and The European Watch and Clock Co. These watch cases were manufactured in Paris, Geneva, London and New York, and each branch was responsible for the production of their own wristwatches. However, the French branch exported its watches to other shops.
Cartiers wristwatches were fast becoming the status symbol of the rich, and people became eager to purchase all the unique models that were being manufactured.
In 1931 Cartier designed its first waterproof wristwatch with a three piece case made in Paris. Other designs to come from Cartier Paris were a covered wristwatch, a shutter wristwatch, a reversible wristwatch a chronograph and a minute repeater.
The 1940's saw a period when the "Moonphase" was a very sort after watch. Its movements were generally by Jaeger or the European Watch and Clock Company. Stainless steel was used during the war when gold became less available."