Short answers, pulled from the story.
Trente Glorieuses is French for "The Glorious Thirty," referring to the thirty years of economic growth in France from 1945 to 1975. The term was coined by French demographer Jean Fourastie in 1979 with the publication of his book Les Trente Glorieuses, ou la revolution invisible de 1946 a 1975. The name is derived from Les Trois Glorieuses, the three days of revolution in France from the 27th to the 29th of July 1830.
The real purchasing power of the average French worker's salary rose by 170% between 1950 and 1975. Overall private consumption increased by 174% between 1950 and 1974. High productivity, high average wages, and a highly developed system of social benefits all characterised the period.
As early as 1944, Charles de Gaulle introduced a dirigiste economic policy, which involved substantial state-directed control over France's capitalist economy. He implemented this after returning to a still partially occupied France, where the economy had been under German occupation control since 1940.
In his 2013 book Capital in the Twenty-First Century, Thomas Piketty described the Trente Glorieuses as an exceptional catch-up period following the two world wars. He cited data showing European growth had dropped to 0.5% between 1913 and 1950, then surged to 4% between 1950 and 1970, before returning to the normal 1.5 to 2% range from 1970 onward.
From 1946 to 1950, France did not achieve real growth. Rationing persisted until 1947 and 1948, a housing crisis was severe, and the cost of living was rising. The economy and infrastructure were described as obsolete, and living conditions remained very difficult for a population still scarred by World War II.
The European Coal and Steel Community, introduced in 1951 under the name Montanunion, replaced trade under supranational High Authority decisions. This increased efficiency and prosperity by removing the restrictions on interchange that had limited trade when borders and tariffs were restored after the war.