The structural parameters of the graphitic carbon overlayer on a Ni(111) substrate has been determined by using surface extended-energy-loss fine-structure spectroscopy. We find that graphitic carbon is very similar to a graphite single-crystal plane, but slightly expanded (\ensuremath{\sim}2%), with C-${\mathrm{C}}_{1}$ and C-${\mathrm{C}}_{2}$ distances of 1.45 \ifmmode\pm\else\textpm\fi{} 0.03 and 2.50 \ifmmode\pm\else\textpm\fi{} 0.03 \AA{}, respectively. The graphite overlayer floats at 2.80 \ifmmode\pm\else\textpm\fi{} 0.08 \AA{} above the Ni(111) face. The C-Ni interaction is strong enough to force the overlayer in registry with the substrate. However, we find that the Ni-Ni distance remains identical, showing that the substrate is not affected by the growth of the graphitic overlayer.