The coupling of fermions to the Standard Model Higgs boson is proportional to their masses. The decay of the Higgs boson to a pair of charm quarks is still unobserved. I will present an overview of a recent direct search for the Higgs decay to a pair of charm quarks, where the Higgs is produced in association with a Z boson decaying to a pair of leptons. The analysis uses a dataset with an integrated luminosity of 36.1 fb-1 of pp collisions at COM energy of 13 TeV recorded by the ATLAS experiment at the LHC. Charm quarks hadronize to produce jets. A novel charm-tagging algorithm is used to identify the jets originating from a charm quark. This technique was used for the first time in this analysis. Charm quark jets are identfied with 41% efficiency, while b quark jets (light flavour jets) are mis-identified as c-jets with a rate of 25% (5%). The observed limit on the production cross section of proton proton to Higgs and Z bosons times branching ratio of Higgs to a pair of charm quarks is 2.7 pb at a 95% confidence level. I will discuss the observed limit in comparison to previous results, and the prospects for further development of the analysis and charm-tagging techniques.