[EN] We consider a realistic model of the synthetic gene circuit combining cell-to-cell communication system via quorum sensing, and a synthetic repressible promoter implementing intracellular negative feedback control. The circuit has been shown to increase robustness with respect to both extrinsic and intrinsic noise elsewhere. As a first step towards an analytic analysis, in this paper we use contraction theory to perform a stability analysis. From it, we infer the components of the circuit most affecting the rate of contractivity, using biologically sensible values of the circuit parameters.This research was partially funded by grant FEDER-CICYT DPI2014-55276-C5-1-R. Yadira Boada thanks grant FPI/2013-3242 of the Universitat Politècnica de València.Picó-Marco, E.; Boada-Acosta, YF.; Picó, J.; Vignoni, A. (2016). Contractivity of a genetic circuit with internal feedback and cell-to-cell communication. IFAC-PapersOnLine. 49(26):213-218. https://doi.org/10.1016/j.ifacol.2016.12.128S213218492