The Couzinet 70 Arc-en-Ciel (Rainbow) was a three-engined commercial monoplane designed for the South Atlantic sector of the France-South America route. First flown in 1929, the Arc-en-Ciel was modified in January 1933 and, as the Model 71, began a regular mail run to South America on 28 May 1934. From 24 July that year there was a regular monthly crossing. The Model 70 was derived from an earlier design, the Couzinet 10-01, which was also named Arc-en-Ciel. The Model 70 made a number of record-breaking pioneer flights.