Vegetal wools are used as an alternative to traditional wall insulator materials, as they present great hygrothermal and acoustic properties, therefore providing interior building comfort. However, one major concern regarding the material's flammability arises, as generally, bio-based materials are poorly classified in terms of flame resistance. Therefore, fireproof treatments are needed and the knowledge regarding their influence on the wool's microstructure, and consequently, on its acoustic and hygrothermal performance, is lacking. This article presents the state of the art and the methodology that will be used to choose and optimize the fireproof treatment on the vegetal wools, and comprehend how it affects the material's microstructure and its acoustic and hygrothermal performances. In order to optimize the performance of the vegetal wools, the final objective of this project will be to develop models to describe the correlation between their micro and macro properties.