Fungi are common biocontaminants of indoor environments, and numerous studies have demonstrated how they can degrade the materials they colonise (e.g. wood, textiles, paper, pigments, varnishes, etc.), which can even result in total destruction of these substrates. Today, fungal contamination is an increasing problem in houses, working places, schools, hospitals, elderly care centers and cultural heritage. Current techniques are unable to detect mould at an early stage in their development or hidden contaminants. Moularat et al. (2008) has established chemical fingerprints of mouldy development from Volatile Organic Compounds (VOCs) arising specifically from fungal metabolism. This approach has the advantage of detecting fungal development both reliably and rapidly before any visible signs of contamination could be detected. Since the development of this Fungal Contamination Index (FCI), other specific indexes have been developed to monitor Invasive Nosocomial Aspergillosis in hospitals or Serpula Lacrymans in dwellings. Their applications constitute a new approach for diagnosis. However, even if the FCI has been widely tested, VOCs'analysis by GC/MS, which is required for index calculation, is incompatible for indoor environment real-time monitoring strategy. So having such a device, which could be set up in buildings and able to provide almost instantaneous information on prospective fungal development, constitutes a breakthrough. In this context, researches around FCI exploitation have been followed up in order to provide a device widely deployable which enables mould development real-time monitoring. This innovative microsystem is the result of the miniaturization of an analytical chain for portable, reliable and low-cost applications. This biodetector was the subject of patent applications by the CSTB.