We observed the microlensing event MOA-2007-BLG-192 at high angular resolution in JHKs with the NACO adaptive optics system on the VLT while the object was still amplified by a factor 1.23 and then at baseline 18 months later. We analyzed and calibrated the NACO photometry in the standard 2MASS system in order to accurately constrain the source and the lens star fluxes. We detect light from the host star of MOA-2007-BLG-192Lb, which significantly reduces the uncertainties in its char- acteristics as compared to earlier analyses. We find that MOA-2007-BLG-192L is most likely a very low mass late type M-dwarf (0.084 [+0.015] [-0.012] M⊙) at a distance of 660 [+100] [-70] pc orbited by a 3.2 [+5.2] [-1.8] M⊕ super-Earth at 0.66 [+0.51] [-0.22] AU. We then discuss the properties of this cold planetary system. ; Comment: published version A&A 540, A78 (2012) A&A, 10 pages, 7 Figures