Precision measurements in the top quark sector with the CMS experiment at the LHC

A review of the measurements of the ${\rm t\bar{t}}$ production cross section (inclusive and differential) performed by the CMS experiment at the LHC is given. The results are used to constrain the magnitude of most of the relevant systematics affecting precision measurements in the top quark sector. In addition from the determination of the top quark pair production cross section it is possible to determine the strong coupling constant as $\alpha_{\rm S}=(m_{\rm Z})=0.1178^{+0.0046}_{-0.0040}$ in agreement with the current world average. After the combination of several channels and techniques explored to measure the top quark mass in data, a precise determination of this quantity is made at CMS: $m_{\rm t}=173.4\pm0.4_{\rm stat}\pm 0.9_{\rm syst}$~GeV. The measurement of the difference $\Delta m_{\rm t}=m_{\rm t}-m_{\rm \bar{t}}$ is also presented.