Herein, we report a model investigation of the adhesion properties between major polysaccharides present in flax fibre and polylactic acid (PLA) polymer matrix, and a correlation between these interactions and the final mechanical properties of the fibre and the composite. The raw flax fibre was first submitted to two separate treatments, an enzymatic and an alkali one, which are known to indirectly promote the fibre-matrix interface adherence. Morphology, mechanical and adherence properties of the treated fibres were measured from nanometer to macroscopic scale. In a second time, we adapt...