You will need to meet Stephane in the art gallery on Leysure Island. He will request 10 photos from you, but you only need to complete the first one for this achievement. Return to Touryst Island to purchase the camera from Axl's shop (if you don't have it yet). Then return to Ybiza and take a picture of Dave, the man operating the elevator for the monument.
Here is a video guide with English commentary!