Deauville is a town in Normandy, France. The coat of arms on the medal is the same as the one on
Wikipedia. So it's safe to assume the medal was made there, or at least made for there. I agree that it is a St Christopher medal; St Christopher medals are very commonly made as religious amulets, St Christopher being the patron saint of travellers.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis