\documentclass[12pt,a4paper]{article}
\usepackage[francais]{babel}
\usepackage{mafr}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{lmodern}
\usepackage[dvipsnames]{xcolor}
\usepackage{pstricks}
\usepackage{pst-eucl}
\begin{document}
\begin{footnotesize}
\begin{pspicture*}(0,0)(6,6)%
\psset{linewidth=.5pt,RightAngleType=suisseromand}%
\pstGeonode[PosAngle={180,-50,90}](1,4){A}(5,1){B}%
\pcline(A)(B)%
\pstMediatorAB{A}{B}{M}{P}%
\pstMediatorAB[PointSymbol=none,PointName=none,linecolor=red,%
			   nodesep=-10,CodeFig=true]{A}{P}{N}{Q}%
\end{pspicture*}
\end{footnotesize}
\end{document}
