[en] Full text: There is a strong recent interest in the use of amorphous carbon (a-C) for non-volatile memory applications. We have conducted a thorough investigation of the unipolar resistance switching mechanism in a-C at the nanoscale. The electrical conduction in a-C thin films is shown to be well captured by a Poole-Frenkel transport model that involves non isolated traps. Moreover, at high electric fields, a field-induced threshold switching phenomenon is observed. The following resistance change is attributed to Joule heating and subsequent localized thermal annealing. We demonstrate that the mechanism is mostly due to clustering of the existing sp² sites within the sp3 matrix. The electrical conduction behavior, field-induced switching and Joule-heating-induced re-arrangement of atomic order resulting in a resistance change are all reminiscent of conventional phase-change memory materials. (author)