Recent research by the British historian Simon Kitson has shown that France did not wait until the Liberation to begin pursuing Nazi collaborators. The Vichy government, itself heavily engaged in collaboration, arrested around 2000 individuals on charges of passing information to the Germans. Their reasons for doing so was to centralise collaboration to ensure that the state maintained a monopoly in Franco-German relations and to defend sovereignty so that France may negotiate from a position of strength. As Kitson has shown the government engaged in many compromises along the way.[5]
After the liberation, France was briefly swept by a wave of executions of suspected collaborators. Women who were suspected of having romantic liaisons with Germans, or more often of being German prostitutes, were publicly humiliated by having their heads shaved. Those who had engaged in the black market were also stigmatized as "war profiteers" (profiteurs de guerre), and popularly called "BOF" (Beurre Oeuf Fromage, or Butter Eggs Cheese, because of the products sold at outrageous prices during the Occupation). However, the Provisional Government of the French Republic (GPRF, 1944-46) quickly reestablished order, and brought Collaborationists before the courts. Many convicted Collaborationists were then amnestied under the Fourth Republic (1946-54), while some civil servants, such as Maurice Papon, succeeding in holding important functions even under Charles de Gaulle and the Fifth Republic (195

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Three different periods are distinguished by historians:[citation needed]
the first phase of popular convictions (épuration sauvage): executions without judgments and shaving of women's heads. Estimations by police prefects made in 1948 and 1952 counted as much as 6,000 executions before the Liberation, and 4,000 afterwards.[citation needed]
the second phase (legal epuration or épuration légale), which began with Charles de Gaulle's June 26 and June 27, 1944 ordonnances on epuration (de Gaulle's first ordonnance instituting Commissions of epuration was enacted on August 18, 1943) : judgments of Collaborationists by the Commissions d'épuration, who condemned approximatively 120,000 persons (Charles Maurras, leader of the royalist Action française, condemned to life sentence on January 25, 1945, etc.), including 1,500 death sentences (Joseph Darnand, head of the Milice, and Pierre Laval, head of the French state, were executed after trial on October 4, 1945, Pierre Pucheu was inculpated end of 1943, Robert Brasillach, executed on February 6, 1945, etc.) — much of which were later amnestied.[citation needed]
the third phase, more lenient towards Collaborationists (the trial of Philippe Pétain or of writer Louis-Ferdinand Céline)
Finally, came the period for amnesty and graces (i.e. Jean-Pierre Esteva, Xavier Vallat, creator of the General Commission for Jewish Affairs, René Bousquet, head of French police, etc.)
Others historians have distinguished epuration against intellectuals (Brasillach, Céline, etc.), industrials, fighters (LVF, etc.) and civil servants (Papon, etc.).[citation needed]
Philippe Pétain, the former head of Vichy France, was charged with treason in July 1945. He was convicted and sentenced to death by firing squad, but Charles de Gaulle commuted the sentence to life imprisonment. Most convicts were amnestied a few years later. In the police, collaborators soon resumed official responsibilities. This continuity of the administration was pointed out, in particular concerning the events of the Paris massacre of 1961, executed under the orders of head of the Parisian police Maurice Papon, who was judged in the 1990s for his role during Vichy.
The French members of the Waffen-SS Charlemagne Division who survived the war were regarded as traitors. Some of the more prominent officers were executed, while the rank-and-file were given prison terms; some of them were given the option of doing time in Indochina (1946-54) with the Foreign Legion instead of prison.
Singer Tino Rossi was detained in Fresnes prison, where, according to Combat newspaper, prison guards asked him for autographs. Pierre Benoit or Arletty were also detained. Collaborationists were brought to the Vélodrome d'hiver, Fresnes prison or the Drancy internment camp.
Many war criminals were judged only in the 1980s: Paul Touvier, Klaus Barbie (who worked after war for the CIA), Maurice Papon (above-mentioned), René Bousquet, head of French police during the war, and his deputy Jean Leguay (the last two were both convicted for their responsibilities in the July 1942 rafle du Vel'd'hiv, or Vel'd'Hiv raid). Famous Nazi hunters Serge and Beate Klarsfeld spent decades trying to bring them before the courts. A fair amount of Collaborationists then joined the OAS terrorist movement during the Algerian War (1954-62). Jacques de Bernonville escaped to Quebec, then Brazil. Jacques Ploncard d'Assac became counsellor of Salazar in Portugal.
Executions without trials and other forms of "popular justice" were harshly criticized immediately after the war, with circles close to Pétainists advancing the figures of 100,000, and denouncing the "Red Terror," "anarchy" or "blind vengeance." Journalist Robert Aron estimated the popular executions to a number of 40,000 in 1960, provoking de Gaulle's surprise, who estimated the real number to be around 10,000, which is the figure today admitted by mainstream historians. Approximatively 9,000 of these 10,000 refers to summary executions in the whole of the country, which occurred during battle. In absolute terms (numbers), there were fewer legal executions in France than in neighbouring, and much smaller, Belgium, and fewer internments than in Norway or Netherlands.[citation needed]
http://en.wikipedia.org/wiki/Pursuit_of_Nazi_collaborators