When to use: Tuple vs Class in C# 7.0

Before Tuples, I used to create a class and its variables, then create object from this class and make that object the return type for some functions. Now, with tuples, I can do the same thing, and in C# 7.0 we can assign understandable names for tuple properties (before this, it was item1, item2, etc..) So now I am wondering, when do I use tuple and when do I create a class in C# 7.0?