The best time to visit Paris is in the spring (Apr-June) or fall (Sept-Nov), when things are easier to come by -- from Métro seats to good-tempered waiters. The weather is temperate year-round. July and August are the worst for crowds. Parisians desert their city then, leaving it to the tourists.
Hotels used to charge off-season rates during the cold, rainy period from November through February; now, they're often packed with business travelers, trade fairs, and winter tour groups, and hoteliers have less incentive to offer discounts. Airfares are still cheaper during these months, and more promotions are available. They rise in the spring and fall, peaking in the summer, when tickets cost the most.
In even-numbered years, don't come to Paris during the first 2 weeks of October without a confirmed hotel room. The weather's fine, but the city is jammed for the auto show.
Holidays in France are known as jours fériés. Shops and banks are closed, as well as many (but not all) restaurants and museums.
