In May-June of 1940, the German military finalized its conquest of France and, with it, claimed ownership of vitally important manpower and aero-industry facilities. This ultimately meant that the "Societe Nationale de Constructions Aeronautiques du Centre" - or SNCAC - now fell under new owners. With the ever-constant need for viable transport aircraft to keep the German war machine humming along, the SNCAC facility at Bourges was directed to produce the German-designed Siebel Si 204 twin-engine light transport / trainer aircraft to ease demand.
This Siebel twin was an original aircraft design - based in the earlier Siebel Fh 104 of 1937, forty-six being completed - developed to a German Air Ministry requirement in 1938. It carried a crew of two with seating for eight, a stepped cockpit, and held many physical features consistent with aircraft of the period - twin rudder fins, leading edge engine nacelles, tail-dragger undercarriage, etc. A total of 1,216 would ultimately be built - though with some wartime help from the French.
With the arrival of war in Europe, the Luftwaffe took the design on as a trainer and Siebel fashioned a step-less, rounded and glazed nose section for better viewing out-of-the-cockpit (similar in scope to the Heinkel He 111). A first-flight was recorded in the middle part of 1940 and service introduction occurred with the Luftwaffe who stocked their inventory with these flight/crew trainers.
For its operational life, the series was powered by 2 x Argus As 410 or As 411 engines. Fifteen prototypes were completed as V1 to V15.
With SNCAC now falling under German control, the aircraft was produced by France from the period of April 1942 until August of 1944 to which 168 examples were ultimately completed for the Luftwaffe. Other variants were also manufactured by other foreign concerns such as Aero Vodochody of Czechoslovakia. The series, as a whole, was in production until January of 1945.
The war ended with a German defeat and a French liberation by May of that year, leaving French aero-industry to pick up the pieces from the devastating occupation period. In the post-war world, the French saw enough value in the aircraft to continue its use though now under the local designation of "NC.700". The line begat variants in the "NC.701", with its rounded, glazed nose section, and the "NC.702", with its original stepped cockpit design.
The French aircraft were powered by Renault 12S-00 V12 inverted air-cooled engines (a copy of the German Argus As 411). SNCAC produced 30 examples of the A-0 model, 85 examples of the A-1 model and 53 examples of the D-1 model for its part in the war (A-0 marked pre-series forms while A-1 was the production passenger model. D-1 aircraft were "blind" trainers).
The NC.701 model was based in the Siebel Si 204D and used effectively as flight/crew trainers complete with dual-control schemes. The NC.702 was born from the Siebel Si 204A and could seat eight passengers. The series in French service was named "Martinet".
The aircraft was operated by both the French Air Force as well as the French Navy in the trainer and light transport roles into 1963. Air carrier Air France operated a modest fleet of the aircraft for a short time until better post-war surplus options became available.