Within the meaning of the European Directive 2002/49/EC, noise assessment relies on the production of strategic noise maps for large cities that are entirely based on numerical simulations. The relevancy of these maps is debatable owing to unquantified uncertainties and to the consideration of a limited number of sound sources. Noise observatories could provide a more complete representation of the sound environments, especially where other kind of sound sources dominates. However, the wide variety of soundscapes from one place to the other requires to rely on a sufficiently high number of devices and consequently to low-cost sensors. The deployment of such sensors for the purpose of environmental noise monitoring is investigated within the framework of the CENSE project that aims at proposing an innovative methodology for producing upgraded noise maps from both simulations and mesurements. A series of innovative noise sensors has been especially designed as part of this research project that are based on MEMS microphones and low consumption microcontrollers, with a cloud connection to central remote servers through a hybrid wireless/wired communication network and power-line communication systems offered by the public lighting network. The designed noise sensors have been qualified under various meteorological conditions in a climate chamber in order to check the potential sensor drift according to both the temperature and relative humidity with a controlled sound load. This communication presents the promising results issued from this experimental campaign and highlights the suitability of the designed sensors for the purpose of environmental noise monitoring.