Do I need a transit visa in Guangzhou?

Hello, I am a Colombian, living in France with a Colombian Passport, I'm traveling to Cambodia but the flight stop in GZ 3 hours (going to Cambodia) and 9 hours (coming back to Paris) do I need to apply for a Chinese entry permit or transit visa to stay at the airport? Can I leave the airport in my way back to know the city for a few hours?
Thanks