Born Jean-Jacques Grosman, he was a journalist and an active member of the French resistance during WWII. During the Liberation he became editor in chief of the newspaper Debout (Standing Up or On Our Feet), which was founded by Claude Julien, another member of the French Resistance. Later he became Chairman of the French National Federation of Former Combatants.
He made his racing debut in a Supercharged Maserati 1500 after the war. Achard drove enthusiastically during 1946 and 1947 as he tried to gain GP driver status. He drove under the banner of his personal racing stable, France Course, managed by Jean Leroy, and sometimes under the Ecurie Atalante banner.
In 1946 he raced an old Bugatti and a Maserati. He managed a sixth at the Albi GP in an Ecurie Atalante Maserati 4CL.
That year, Ecurie Blanche et Noire borrowed the Delahaye 155, the only true GP Delahaye. The car showed up in Nice for scrutineering, but for some reason it was not allowed to race. Then when Ecurie Blanche et Noire disappeared mid-season, the Delahaye was entrusted to Achard. He entered it for the Trois Villes Circuit under the Ecurie Atalante banner in August 1946 but did not start. He had qualified in fourth and was the fastest of the French cars. Unfortunately come race time he could not get it started and was disqualified.
In 1947 Ecurie Gersac was officially presented to the press on April 1st at its premises in Paris, 24 rue François-Bonvin. The three cars had a new badge: a chromium-plated circle with an Ecurie Gersac inscription, instead of Ecurie Walter Watney as at Monthléry. Henri Louveau was the technical director of the Ecurie and its top driver. Phi-Phi Etancelin, Pierre Levegh, Achard and Maurice Trintignant were the drivers.
In 1947 Achard drove an Ecurie Gersac Delage D6.70 finishing 4th at the Pau GP in April then, later in the month, at the Grand Prix du Roussillon in Perpignan he crashed out on the 7th lap. He raced a Simca in the Bol d'Or and took an 8th in the Jersey Road Race in the Delage in May, followed by a sixth at the Marseille GP 10 days later. At Nimes in June he crashed on the first lap, while the V12 Delahaye 155 that he had used in1946 was lent to Levegh for the race.
Achard then drove the Delahaye again on July 13th in the Grand Prix de l'Albigeois at Albi. However he crashed badly when the car lost a wheel, killing a lady spectator. Achard was also injured and failed to recover in time for the Comminges GP in August. He didn't race again in Europe but at the end of 1950 when Philippe Etancelin, by then in his mid 50's, retired, Achard acquired his 1948 Talbot Lago T26C (110008).
In January 1951 Achard moved to Brazil, taking the Talbot with him with the intention of racing in local events and also entering the Indianapolis 500. That year he raced at Interlagos on May 13th, finishing 5th and at Boavista on June 24, finishing 3rd. The Talbot was then sold to a local Brazilian driver, Pinheiro Pires.
It was at the wheel of Pinheiro Pires' Ferrari that Achard crashed with fatal consequences while competing in the Rampa de Gávea, a hilclimb held on part of the Gávea track. He took off at high speed but apparently got confused with the pedals of his Ferrari as his Talbot had the throttle and brake pedals arranged in inverted positions, the accelerator being in the center, and crashed headlong into a wall.