The fundamental difference between the two is that genuine leather is made from animal hides, such as cattle, buffalo, deer or oxen. Faux leather is made from a plastic base and is then treated with wax, dye or polyurethane to create the colour and texture.
You have probably smelt a bag to determine if its leather or not. The fake leather bags will smell like plastic and chemicals and will disintegrate quickly. They are also considerably cheaper to make, and yet in Australia, they are expensive to buy.
We have also yet to find a synthetic bag with a 12 month warranty….I wonder why!