Occupation: the ordeal of France 1940-1944 by Ian Ousby John Murray, pounds 25
The bitter legacy of France's occupation by the Nazis - her "poisoned memory", as one writer has put it - is with us still. A fortnight ago, a ceremony of repentance was held in the Paris suburb of Drancy, where tens of thousands of Jews were interned on their way to the concentration camps, to acknowledge the French Catholic Church's failure to condemn the Vichy regime's treatment of Jews during the Second World War. Last week saw the opening of the trial of 86-year-old Maurice Papon, former Vichy Secretary-General of the Gironde, who is accused - like Klaus Barbie and Paul Touvier before him - of "crimes against humanity".

In his compelling account of those bleak years, Ian Ousby traces the roots of France's capitulation and her mood of defeatism in May 1940 to the scars inflicted on national memory by the huge loss of life during the Great War. In 1916, however, the citadel fortress of Verdun withstood the enemy for 10 months; in 1940, it succumbed in a day.

As the German armies advanced on Paris and the French government moved in panic from Bordeaux to Clermont-Ferrand, and finally to the spa town of Vichy, the 84-year-old Marshal Petain - the "victor of Verdun" in popular legend - answered his nation's call once more. "I make to France the gift of my person, to attenuate her suffering," he broadcast to the French people in his high, thin, authoritative voice ("like a skeleton with a chill" was how Arthur Koestler described it). "The combat must cease," he continued. So it was that in the same railway carriage in the forest of Rethondes where in 1918 Marshal Foch had accepted the German surrender, Philippe Petain signed the Armistice and paved the way for the policy of collaboration that was to stain and divide his nation.

Petain's and Laval's initial hopes for collaboration a raison were based on an acceptance of the harsh realities imposed by the German presence, yet they also clung to a pathetic belief in a theory of National Revolution, a notion of a "New European Order" in which France would play its subsidiary part alongside the Reich. France would stand firm against the menace of Bolshevism, check the powers of Jews and Freemasons - who, they believed, had brought the nation to its sorry plight - and restore the conservative values of "Travail, Famille, Patrie", in the words of the slogan adopted by the new regime.

While a little-known colonel, Charles de Gaulle, lit the first tentative flames of resistance in London, Andre Gide observed in his diary that "France now is no longer France". As for Paris, she "was peopled by the absent", in Sartre's memorable phrase. Swastikas flew over the city and the soldiers of the Wehrmacht paraded daily down the Champs-Elysees. The nation was divided not just between those who had supported collaboration or resistance, but between Occupied and Non-occupied zones, city and country, profiteers and the exploited - between Frenchman and Frenchman. Ousby does not mince his words: "in the atmosphere of Vichy, self-interest flourished happily beside conviction or apparent conviction and could easily triumph over it if the need arose".

By 1943, any illusions about Nazi intentions had crumbled. Expediency dictated the Reich's policies, and with the failure of its armies on the Eastern front and an increasing demand for French forced labour to sustain the war effort, a wave of hostility and anger gradually came to replace the defeatism of 1940. Ousby tracks the change of national mood that led from the narrow ultra-conservatism and meek acceptance of the German diktat to the growth of resistance in 1943 and 1944, when many conveniently switched allegiances, right up to the Liberation and the brutalities of its epuration (purge), and to De Gaulle's successful attempt to create a myth of resistance that might heal the wounds of 1940. His book is a valuable distillation culled from the vast amount of literature on the subject available in French, and it provides a wealth of intriguing detail about daily life and contemporary attitudes. The true face of la France eternelle, he reminds us, was not reflected by Vichy. Nor should later generations seek to apportion the blame for French dishonour solely on one man: the genuinely tragic figure of Marshal Petain.