The Saar's extensive coal deposits led to industrial development following German unification in 1871. After World War I, the Saar was placed under the administration of the League of Nations for a period of fifteen years, with France to receive its coal production during that period to compensate France for the deliberate destruction of its coal mines by retreating German troops. At the end of the fifteen-year period, Saarlanders were to vote on their future. In a plebiscite held in January 1935, 90 percent of voters in the Saar opted to return to Germany.
After World War II the Saar passed under French military administration, and in 1947 the French set up an autonomous government for the region. In a plebiscite that year, the voters of the Saar approved economic unification with France, and a customs union went into effect in 1948. The other Western powers recognized this arrangement, much to the chagrin of West German leaders. France was obliged to give ground, however, for the 1954 Paris Pacts that provided for West German rearmament and its integration into the North Atlantic Treaty Organization (NATO) also provided for a compromise settlement of the Saar question. To the relief of the Germans, the Saar was declared to be autonomous rather than politically integrated into France. However, it was to remain economically integrated with France for fifty years. But Saar voters threw a monkey wrench into this arrangement by rejecting it in October 1955.
The 1952 European Coal and Steel Community (ECSC), which marked the movement toward the European Economic Community (EEC), and West Germany's integration into the Western alliance eased French concerns over the future of the Saar. As a result of the 1956 Franco-German Agreement, the Saar became a West German territory on 1 January 1957. Although the customs union with France was dissolved in July 1959, France was granted the right to exploit the Saar's Warndt coalfields until 1981.
Freymond, Jacques. The Saar Conflict, 1945–1955. New York: Praeger, 1960.; Staerk, Dieter. Das Saarlandbuch. Saarbrücken: Minerva-Verlag Thinnes and Nolte, 1985.