A facility for producing a composite material that includes carbon nanotubes. The facility includes a reaction chamber with an injection device for injecting an active gas mixture (for the growth of the carbon nanotubes) into the interior volume thereof. A transport device is to transport a substrate into the reaction chamber to form the composite material. The injection device may transport the active gas mixture in a first direction into the interior volume. A circulation device is to circulate the active gas mixture, and may transport the active gas mixture into the interior volume in a second direction that is different from the first direction. The circulation device may adopt a first configuration of injection of the active gas mixture into the interior volume of the chamber, and a second configuration of extraction of the active gas mixture from the interior volume.