
\documentclass{article}
  \usepackage{diagbox}
  \pagestyle{empty}

\begin{document}
\begin{tabular}{|l|c|c|c|c|c|c|}
\hline
\diagbox{qui}{quoi} & 
 voiture & tente & corde \\ 
\hline
Nico   & 1 & 1 & 1 \\ \hline
Hélène &   &   & 1 \\ \hline
Tof    &   & 1 & 1 \\ \hline
Xav    & 1 &   &   \\ \hline
\end{tabular}
\end{document}
