To me, the bigger risk is the mail system in International sales. US international mail, International Priority Mail and the like, are all trackable and reliable in the U.S, but once they leave here, it's up to the local post office to make the delivery. In France, the UK, Germany and many other EU countries, the mail system is equal to our own in efficiency, and you can track a package door to door. However, in Spain, Greece, most of Asia, Africa and South America, packages can get hung up in customs for weeks, then disappear without a trace. Delivery can't be confirmed or denied, which leaves the buyer free to file a "package did not arrive" complaint with PayPal and get their money back from you.
Some unscrupulous people use this fact to get a lot of "free" stuff from eBay.
Alternatives like UPS, FedEx and DHL are trackable door to door, and very fast, but also cost an arm and a leg.
Just be careful when shipping internationally. With France, you should have no problems at all.