Amateur performers are frequently portrayed in the French cultural landscape for their negative impact on their artistic environment. From a legal and economic perspective, they are accused of triggering an uncomfortable situation for professional performers, downgrading their livelihood by installing an unfair competition over the music and acting job markets. This perspective prevents both the legal and mediatic bodies from fully catching the larger issues covered by amateurism in live performing arts, especially from a social and artistic point of view. The amateur suffers from a damaged image, systematically compared to professional performers and appears altogether as a threat and as a fraud. Following the cultural rights and cultural diversity promotion movement, this work aims to explore the roots of this conflictual connection and to document the forms it might take. Fieldwork involves a hundred and fifty interviews conducted with artists, agents and venues, planning on observing the many ways they work and reflect upon music and theatre. The study is rooted in Brittany, France, and implies three local scenes: one aims to tackle the acting scene while the two others aim to shed light upon two ways of performing popular music, through the study of the fest-noz and rock music scenes. The relevance of the amateur versus professional bipolar partition as shaped by law and funding bodies will then be evaluated using the grounded theory method, allowing other subcategories to emerge in the light of artistic pluralism. It will then be assessed through a combination of exploratory and comparative research work, demonstrating that other classificatory frames might prove useful.