De Gaulle believed that while the war in Algeria was militarily winnable, it was not defensible internationally, and he became reconciled to the colony's eventual independence. This stance greatly angered the French settlers and their metropolitan supporters, and de Gaulle was forced to suppress two uprisings in Algeria by French settlers and troops, in the second of which (the Generals' Putsch in April 1961) France herself was threatened with invasion by rebel paratroops. De Gaulle's government also covered up the Paris massacre of 1961, issued under the orders of the police prefect Maurice Papon. He was also targeted by the settler Organisation armée secrète (OAS) terrorist group and several assassination attempts were made on him; the most famous is that of 22 August 1962, when he and his wife narrowly escaped an assassination attempt when their Citroën DS was targeted by machine gun fire arranged by Jean-Marie Bastien-Thiry in Petit-Clamart. After a referendum on Algerian self-determination carried out in 1961, de Gaulle arranged a cease-fire in Algeria with the March 1962 Évian Accords, legitimated by another referendum a month later. Algeria became independent in July 1962, while an amnesty was later issued covering all crimes committed during the war, including the use of torture. In just a few months in 1962, 900,000 French settlers left the country. The exodus accelerated after the 5th of July 1962 massacre.