\documentclass[11pt,a4paper]{article}
\usepackage{amsfonts,amsmath,amssymb,mathrsfs}
\usepackage[francais]{babel}
%\usepackage[T1]{fontenc} % pour PC
\usepackage[applemac]{inputenc} % pour Mac
%\usepackage[utf8]{inputenc}% pour PC
\usepackage{answers}
\usepackage[thmmarks,amsmath]{ntheorem}

\usepackage[top=1.5cm, bottom=1.5cm, left=1.5cm, right=1.5cm]{geometry}
\setlength{\parindent}{0cm}

%---- Structure Exercice -----
\theorembodyfont{\normalfont}
\newtheorem{Exc}{Exercice}\Newassociation{correction}{Soln}{mycor}
\renewcommand{\Solnlabel}[1]{\textbf{\emph{Corrig\'e de l'exercice #1}}} 
\def\exo#1{\futurelet\testchar\MaybeOptArgmyexoo}
\def\MaybeOptArgmyexoo{\ifx[\testchar \let\next\OptArgmyexoo
                        \else \let\next\NoOptArgmyexoo \fi \next}
\def\OptArgmyexoo[#1]{\begin{Exc}[#1]\normalfont}
\def\NoOptArgmyexoo{\begin{Exc}\normalfont}
\newcommand{\finexo}{\end{Exc}}
\newcommand{\flag}[1]{}
\newcommand{\entete}[1]


\begin{document}
%\pagestyle{empty} 

 \Opensolutionfile{mycor}[ficcorex]

\exo{}$\ $

\'Enonc\'e de l'exercice 

\begin{correction} $\ $\par 
Corrig\'e de l'exercice
\end{correction}

\finexo

\newpage
\setcounter{page}{1}\Closesolutionfile{mycor}\Readsolutionfile{mycor}


\end{document}