Personally I've never heard of a cafe crème before, but one website says it's an espresso to which you add a bunch of milk. Another website says it's supposed to be less foamy than a cappuccino and less milky than a latte. Found a swiss Site which makes it sound even more complicated.

As for the others.. lungo and allongé are the same thing, which is usually an espresso but you let more water flow through the coffee. Usually at least twice as much. Americano is usually just an espresso to which you add a bunch of hot water. Usually to fill one of those bigger mugs till you get to like 150-200ml