Controls rather than entry restrictions

France reestablished the passport by the decree of 3 August 1914. A visa was only required when Americans wanted to leave France to travel elsewhere in Europe and then return to France. They were also subject to French customs (heavy duties) but without particular annoyances.
As of 2 April 1917, they were, like all foreigners, required to have an ID card, but at the Prefecture of Police in Paris, a special section was reserved for them, along with the English. The social breakdown of those entering—merchants, professionals, manufacturers, financiers, intellectuals, skilled tradesmen, artists—indicates that the Americans were mostly in the category of “non-salaried” foreigners, which spared them the mark associated with the ID for industrial or agricultural workers (which implied an inferior status).
The Americans involved in commerce had to have a professional ID. As of 1936, even American tourists (less and less numerous) were also required to have a tourist card. To this day, I have not encountered cases of exclusion, deportation or extradition of Americans from France.
Freedom of enterprise
What interested the Americans were the careers and private businesses of France’s tertiary sector that were based on freedom of enterprise—banks, insurance companies, business services, sales offices, import-export, tourism, transportation, travel, press, health, teaching, art, education. In the tertiary sector, Legislation concerning French citizens was almost nonexistent, and that aimed at foreigners even more so. It was an extremely open sector. Thus, the Americans were not subject to control by French employers (they were not affected by the restrictive laws of the 1930s) but by their own compatriots. The American partners applied French laws on wages and social-security benefits (work injury, 40-hour work week, paid vacations etc.). American shopkeepers in France were required to be listed in the trade register and pay the small-business tax.

French ostracism and American responses

Americans were hardly bothered by the fact that they could not become lawyers because the attorneys within the American community in France had no desire to be admitted to the French bar. They preferred their extraterritorial situation. What was more troublesome, however, especially at the American Hospital in Paris, was the fact that they could not recruit American doctors (although, after years of negotiations, they ultimately succeeded in obtaining the presence of at least six American practitioners through the specific law of 18 May 1949).
Americans were excluded from the so-called “prorogation laws” (legally maintaining tenants in their apartments) which were intended to confront the housing crisis at the end of the war. But via diplomatic channels, they obtained an “interpretive agreement” which officially gave them the same rights as French citizens.
American companies and individuals were taxed twice, in France and in the United States. The Americans of France failed to get this double taxation eliminated for individuals but succeeded in improving the lot of companies through a bilateral agreement between France and the United States stipulating exoneration measures.
Seizing opportunities
Making little use of the right to the free, secular, required education that they could have received; the Americans preferred to give their children an American-style education in private, tuition-paying schools (from primary to high school). After high school, the young people often went to study in the United States.
On the other hand, they fully benefited from the right of free association established by the law of 1901 to set up numerous private American associations in France. These were totally autonomous because they were composed of American volunteers and funded by the colony. They existed in all areas—religion, health, mutual aid, leisure activities, culture, education, trade, defense of the colony’s interests—and they permitted an American national identity to be maintained abroad.