The airline group also secured purchase rights for a further 60 planes, to renew the KLM and Transavia Netherlands fleets and expand the Transavia France fleet.
The first deliveries of the Airbus A320neo and Airbus A321neo aircraft are expected in the second half of 2023.
Compared to previous generation aircraft, they reportedly offer a unit cost reduction of more than 10%, as well as a 15% reduction in fuel consumption and CO2 emissions. Their noise footprint is also 50% lower.
Alongside the use of sustainable aviation fuels and eco-piloting, fleet renewal is "one of the pillars" of the group’s decarbonisation trajectory, which aims for net zero emissions by 2050, and -50% CO2 emissions per passenger per km by 2030.
The aircraft will operate medium-haul routes in Europe, notably from Amsterdam-Schiphol and Paris-Orly.
Air France-KLM also signed a Letter of Intent (LOI) for the purchase of four Airbus A350F Full Freighter aircraft, with purchase rights for four additional planes to increase cargo capacity at Air France.
Benjamin Smith, chief executive of the Air France-KLM Group, said these "evolutionary orders" will position the group’s airlines "on the path to improved performance" while "accelerating our decarbonisation trajectory".
"This is a major step forward for KLM, Transavia and Air France, which will operate the best aircraft available for their network needs," he added.