Carbon fibers widely used in automotive, aerospace and energy present the advantage over conventional materials of combining low weight and high strength. This advantage is counterbalanced by their significant cost and the release of toxic substances during carbonization. Bio-sourced cellulose materials-like and eco-friendlier plasma carbonization technologies will help to overcome these challenges. The dependence of the carbonization yield on the plasma parameters (pressure, power, duration...) is illustrated showing that it is a fast process leading to an efficient carbon fiber well characterized for the chemical, morphological and mechanical aspects. Indeed, the plasma-carbonization of stretched cellulose fibers containing various CNT proportions (0 %, 0.01 %, 0.1 %, 0.3%, 0.6%) gives rise to an important residue close to the theoretical value (44.5%). The synthesized and surfacefunctionalized homogeneous, non-porous carbon fibers present a high ratio of Raman D/G bands reflected a high yield of the carbon organization and, therefore, inducing good mechanical properties. The plasma-carbonization mechanism essentially involves the ejection of hydroxyl groups from cellulose and their subsequent dissociation in plasma.