From her book Lucie Aubrac: The French Resistance Heroine Who Defied the Gestapo:
"In the summer of 1940, when Paris was struggling with the new Occupation, a Socialist called Jean Texcier had produced a Manual of Dignity which was secretly passed from hand to hand. Included in his 'Advice to an Occupied Population' were semi-facetious suggestions - soldiers asking for directions in the street should be courteously sent the wrong way, for example. But Texcier's message was a serious one. 'Husband your anger,' he wrote, 'for you may need it [and] have no illusions: these men are not tourists.'
Now Liberation began to write its own editorials on how to deal with the conquerors in their midst: Whenever Germans arrived in cafes or restaurants, all French should ostentatiously rise and leave; swastika should be chalked on buildings belonging to industrialists or merchants who worked with the invader; and patriotic bunting should be hung in the streets on the anniversary of the Battle of the Marne, when French troops had soundly beaten the Germans in 1914."