Urban frugality is a development project for a Haussmann-era apartment, which proposes a new architectural language based on bio-geosourced materials such as raw earth, wood, stone, cellulose and wool. The aim is to highlight the raw material in its most natural aspect in order to benefit from its ecological and technical advantages while asserting its raw aesthetic. This project therefore explores the rural and rustic connotations usually attributed to these materials in order to overcome them by confronting them with a sophisticated urban universe and thus testify to their creative potential.