The RATP bus network covers the entire territory of the city of Paris and the vast majority of its near suburbs.

Operated by the Régie Autonome des Transports Parisiens (RATP), this constitutes a dense bus network complementary to other public transport networks, all organized and financed by Île-de-France Mobilités.

Other suburban bus lines are managed by private operators grouped in a consortium known as Optile (Organisation professionnelle des transports d'Île-de-France), an association of 80 private bus operators holding exclusive rights on their lines.

There are approximately 9500 buses serving public transportation across the Paris region, all operators included.

Bus lines operated mainly in the suburbs are named with a three-digit number code.