Post offices, found in every town, are recognizable by a yellow La Poste sign. They're usually open weekdays from 9 or 9:30 am to 5 pm, and Saturday from 9 am to noon.
Letters and postcards to the United States and Canada cost €1.20 for 20 grams. Stamps can be bought in post offices and in cafés displaying a red tabac sign outside. It takes, on the average, four days for letters to arrive in Europe, and five days to reach the United States.
If you're uncertain where you'll be staying, have mail sent to the local post office, addressed as poste restante. The French postal service has a €0.58 per item service charge.
Sending overnight mail from major cities in France is relatively easy. Besides DHL, Federal Express, and UPS, the French post office has overnight mail service, called Chronopost, which is much cheaper for small packages. Keep in mind that certain things cannot be shipped from France to the United States, such as perfume, fresh food, or any meat products.