Alain Robert, 48, scaled the 27-story building without ropes or equipment. Rescue workers set up an inflatable bag just in case he fell.
Robert said his climb was an attempt to bring attention to Hong Kong's pollution problem and appealed to the government to make changes.
"I'm still a green campaigner, especially Hong Kong is quite polluted. But, you know, I can only raise awareness by talking, but there is not much that I can do," Robert said.
Robert was arrested and released without charge.
Robert has climbed more than 70 skyscrapers around the world, including the Empire State Building, Chicago's Sears Tower and the Petronas Towers in Kuala Lumpur, according to his website.