High resolution characterization by Atom Probe Tomography (APT) and Secondary Ion Mass Spectrometry (SIMS) imaging were combined to highlight the nature of chlorine contamination and impact of deposition temperature for chemical vapor deposited Ti(C,N) thin hard coating. It is highlighted that chlorine is spread and segregates exclusively at the grain boundaries. With increasing temperature (at 930°C), columnar grains of Ti(C,N) become coarser and chlorine segregation at the grain boundaries is reduced about 3 times in comparison to lower temperature (at 885°C). It also appears that chlorine is less homogeneously distributed with chlorine rich/free regions as it is demonstrated by the powerful combination of nano-SIMS and APT which gave a great insight of the spatial distribution of segregating elements at grain boundaries at nano- and micrometric scales.