The plan was approved in July 1966 by President Charles de Gaulle, in the aftermath of two key events that made his government worry about French dependence on the US computer industry.

[1] In the mid-1960s, the United States denied export licenses for American-made IBM and CDC computers to the French Commissariat à l'énergie atomique in order to prevent it from perfecting its H bomb.

[1][2][3][4]: 21 [5][failed verification] Meanwhile, in 1964, General Electric had acquired a majority of Compagnie des Machines Bull, the largest French computer manufacturer, which had the second highest market share in France, after IBM, and was a leading IT equipment maker in Europe.

[3][8] Responsibility for administering the plan was given to a newly created government agency, Délégation générale à l'informatique [fr] (Information Bureau), answering directly to the prime minister.

Yet a new President of the Republic was elected then, former Finance minister Giscard d'Estaing, who was a strong opponent of the Plan Calcul; meanwhile, CII's sleeping partner, CGE-Alcatel, woke up to oppose the domination of its archrival Siemens over the European computer industry.