Mid-infrared free-space absorption spectrometers have demonstrated label-free and real-time detection of multiple chemical and biological substances with an outstanding precision and versatility. However, they are bulky and high-cost, precluding their use in widespread high-volume applications. The MIR-Spec project will address these limitations by developing innovative silicon on-chip mid-infrared absorption spectroscopy sensors. The ground-breaking concept is to use subwavelength silicon nano-structures to develop a novel platform that leverages the wide transparency (up to ~8 µm wavelength) and large-volume fabrication processes of silicon, leading to significant breakthroughs in sensing applications. The MIR-Spec project is a “Projets de recherche collaborative - entreprises (PRCE)”, which gathers an academic research group (C2N), a Si foundry (STMircroelectronics) and an end-user (MirSense).