In 1922, by liberal interpretation of the rules, Voisin had won the Grand Prix of Lyon. The organisers were unhappy with the result and banned the car design for the following year. In response, Voisin evolved an entirely new concept; the C6.

It is always difficult to obtain the same horsepower from a sleeve valve engine compared to one with conventional valves. In addition, Voisin did not have an engine of the required 2 litres. He therefore asked André Lefèbvre to design a light car with good aerodynamics which would compensate for the lower power of Voisin engines. This is how the Laboratoire was conceived in 1923 and was probably the first race car which attempted to obtain stability using aerodynamics and was the first monocoque car.

The barely tested engine was the weakest link, and the poor power output resulted in the car not shining in the race. Additional cooling was necessary and the rear differential was dispensed with to reduce weight. Only one Voisin finished the race in fifth place.