the end of World War I, Paris replaced Vienna as the cultural capital of Europe, if not of the world. Many foreigners settled in Paris during this period, some briefly and some long-term, some exiles and some voluntary, because of Paris's tolerance for unorthodox sexuality, politics, and art. The movement built on itself, as the more intellectuals and artists moved to Paris, the more attraction it had for others. Among the Americans living in Paris during this period are Paul Bowles, Aaron Copland, Ernest Hemingway, Henry Miller, Ezra Pound, Gertrude Stein, and Alice B. Toklas. World War II When France officially declared war on Germany in September 1939, as a response to the Third Reich's invasion of Poland, an estimated 30,000 Americans lived in or near Paris. Although that declaration was followed by roughly nine-months of what often was called the "phony war" or "drôle de guerre," the inevitability of coming conflict led most of those expatriates to leave France while they could. In June 1940, the inevitable occurred with massive German attacks and after scarcely three weeks of battle, Nazi troops marched uncontested through the gates of Paris and some 5,000 Americans still were in the French capital. For various reasons, such as family ties and professional obligations, they had chosen to remain in Paris. At that moment, the United States was not at war, however, and not militarily allied with anyone. It was still a neutral nation. German occupying forces were legally obligated to treat U.S. citizens better than French nationals even though many were bi-nationals with French passports as well as American ones. Americans who stayed in the capital endured most of the shortages and hardships of their French neighbors but to some extent for nearly a year and a half they were not imprisoned by German occupying authorities. However, their lives were not easy and often tragic, in particular for African-Americans and Jewish Americans who were frequently singled out by the Nazis for harsher than normal treatment. Because the United States still remained neutral, the German occupying forces at first allowed long-standing institutions in the French capital such as the American hospital, the American library, the American church, the American Chamber of Commerce as well as various others of a commercial or charitable nature to remain open. When the United States entered the war, it led to a clamp down on U.S. citizens in German-occupied northern