\documentclass[11pt]{lettre}
\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[frenchstyle]{kpfonts}
\usepackage[frenchb]{babel}


\begin{document}
\institut{pp_adresse}
\begin{letter}{§RECIPIENT§}
\signature{§SIGNATURE§}
\opening{§HELLO§}

§BODY§

\closing{§GOODBYE§}
%\cc{Cclist}
%\ps{adding a postscript}
%\encl{list of enclosed material}
\end{letter}
\end{document}