Shortly afterwards, French automaker Panhard approached Deutsch to design a successor to his DB HBR 5 for the 1962 24 Hours of Le Mans.

Panhard gave approval for work to start on the car at the end of January 1962, and factory manager Etienne de Valance began to build a team of drivers.

Five cars were built; one prototype with a body of hand-hammered steel and four more with bodywork in glass-reinforced plastic (GRP) by Chappe et Gessalin.

[2] The engines were the air-cooled boxer twins designed by Panhard's Louis Delagarde and tuned by Deutsch and Société Moteur Moderne.

The coupé first appeared at the Le Mans test days in April 1962, where the car was registered in the class for prototypes with engines of up to 850 cc (51.9 cu in).

Number 54 was eliminated in the ninth hour of the race due to an accident in which the car overturned and caught fire.

The car also placed third in the "Indice au rendement énergetique", or consumption index, with an average of 11.4 L/100 km (24.8 mpg‑imp; 20.6 mpg‑US) with a 590 kg (1,300.7 lb) vehicle weight.

On 16 September, Deutsch brought a CD Dyna with a modified engine and some additional aerodynamic changes to the Hunaudières straight where the car reached a top speed of 204 km/h (126.8 mph).

[4] In 21 October 21 1962, drivers André Guilhaudin and Alain Bertaut finished in 20th position at the 1000 km race of Paris.

The lightweight body was made of fibreglass, which lent itself to the curvy shape and the economies of a small production run of vehicles.

The body was mounted on a torsionally-rigid central backbone frame that followed the pattern set by earlier DB designs.

The engine in the GT was a standard model fed by a single Zenith type 38 NDIX down-draught carburetor that made 36.5 kW (49 hp).

The four-speed gearbox was a Panhard component with a direct-drive third gear and overdrive fourth that drove the front wheels.

Braking was by System ETA (évécuation thermale accéléré), with a light alloy drum on the outside of the wheel for cooling and an iron lining.

These cars retained the central backbone chassis from the production Panhard CD, revised by Jean Claude Haenel.

He produced a shape with completely covered headlamps, smooth sides with front and rear wheel spats and a smooth underfloor with a section towards the rear of the car shaped like a diffuser in an early use of "effet de sol" or "ground effect" to produce down-force.

[6]: 90 Due to safety concerns, cars with engines smaller than 1 litre were not allowed to run at Le Mans beginning in 1964.

[7] To overcome that restriction, the engine in the LM64s received a Sferma supercharger along with other changes that included twin-ignition and dual Zenith carburetors.