The design anticipated the government specification MT/CPT-9 for a "combat scout seaplane" for the Forces Aériennes de Mer, which was circulated amongst manufacturers in May 1935.

When the NC.4-10 first flew, piloted by Lucian Coupet on 10 July 1939, it was powered instead by a pair of 890 hp (635 kW) Gnome-Rhône 14Knrs/ors 14-cylinder radials, mounted on the upper wing surface.

After a few flights, these proved to be poorly cooled and to be prone to crankshaft failure, so they were replaced with 1050 hp (780 kW) Gnome-Rhône 14 N1/N2 radials.

[1] Conversely, the Admiralty had changed its mind and chosen to abandon the floatplane in favour of landplanes, ordering the Lioré et Olivier LeO 45.

The seaplanes of specification MT/CPT-9 ultimately remained in use for miscellaneous tasks, the NC.4-10 going to St Raphael for tests of speed, service ceiling and range.