STORY: Video posted on social media also showed protesters, many wearing red gilets and holding flags and banners, gathered inside the terminal with passenger check-in facilities seen in the background.
The spontaneous protest which started around 0730GMT is not impacting flights, a spokesperson for Aeroports de Paris said.
Protest rallies were scheduled across the country later in the day, while protests also targeted oil depots and blocked an LNG terminal in the northern city of Dunkirk.
The latest wave of protests represents the most serious challenge to the president's authority since the "Yellow Vest" revolt four years ago. Polls show a wide majority of French opposed to the pension legislation as well as the government's decision to push it through parliament without a vote.