% Dans le préambule
% -----------------
\usepackage{tikz,tkz-base}
% -----------------

\begin{tikzpicture}
\tkzInit[xmin=-2,xmax=4,
         ymin=0,ymax=1,ystep=0.5]
\tkzAxeX[trig=3,label options={below = 8pt}]
\tkzAxeY[frac=2]
\tkzDefPoint(pi,0.5){A}
\draw(A) node{$\bullet$} node[above]{$A$};
\end{tikzpicture}