% Dans le préambule
% -----------------
\usepackage{calc}
% -----------------

% Dans le préambule
% -----------------
\usepackage{textcomp}
% -----------------

\newlength{\HA}      \newlength{\LA}
\setlength{\HA}{7mm} \setlength{\LA}{1cm}

\newsavebox{\boxA} \savebox{\boxA}{4\texteuro}

\newsavebox{\boxB} \savebox{\boxB}{la séance !}
\newlength{\HB} \newlength{\LB}
\setlength{\HB}{\totalheightof{\usebox\boxB}}
\setlength{\LB}{\widthof{\usebox\boxB}}

\resizebox{\LA}{\HA}{\usebox\boxA}

             \rule{\LB}{1pt}%
\hspace{-\LB}\rule[\HA-1pt]{\LB}{1pt}%
\hspace{-\LB}\raisebox{\HA/2-\HB/2}{\usebox\boxB}