You can have a article in the center of the parallax background. You can even apply a super cool blur effect on the background and use the same image to the right. You can use any html content, like sliders, etc. as usual.

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.