Compared to the latter, the two major differences of the DR400 are a wider cabin at shoulder level and a forward-sliding canopy, a new concept introduced with the Robin HR-1 in 1969[3][page needed], made to replace the doors present on earlier series.

The dashboard is also clearer and more elevated than on previous models, allowing easier instrument readings.

[citation needed] The main difference between DR400 models is the engine, as the cabin remains identical between versions.

[citation needed] The design of the aircraft is old; it consists of a wooden canvas structure with a low, positive-dihedral wing.

In 2019, French air clubs operated 864 DR300 and DR400 models out of the 2394 training and rental aircraft available nationwide.

[citation needed] Due to its attractive price and good performance characteristics, the "Dauphin 2+2" is the most sold version of the DR400 family and remains so in the 21st century.

A noticeable difference is that some aircraft are not equipped with pedal-brakes but rather with a brake handle located between the two front seats.