\documentclass[8pt]{scrreprt}
\usepackage{fontspec}
\usepackage{xunicode}
\usepackage{polyglossia}
\usepackage[margin=1in, paperwidth=12cm, paperheight=12cm, top=0.5cm, bottom=0.5cm, left=0.5cm, right=0.5cm]{geometry}

\setmainlanguage{french}

\title{La lumière s'éteint-elle dans le frigo~?}
\subtitle{Étude d'un bus en vue d'acquisition de données}
\author{Nathanaël Restori}
\date{\today}

\begin{document}

\begin{titlepage}
    \makeatletter
    \begin{center}

        \textsc{\LARGE Gymnase de Burier}\\[1cm] 

        \textbf{\huge \@title\\[0.5em]
        \large \@subtitle}

        \vfill

        \begin{figure}[htp]
            \centering
            \includegraphics[width=1\textwidth]{figures/Arduino_Ethernet.jpg}
        \end{figure}

        \vfill

        \begin{minipage}{0.59\textwidth}
            \begin{flushleft}
                Blonay, le \@date
            \end{flushleft}
        \end{minipage}
        \begin{minipage}{0.4\textwidth}
            \begin{flushright}
                \@author, 2M6\\
            \end{flushright}
        \end{minipage}

    \end{center}

    \setcounter{page}{0}
    \makeatother
\end{titlepage}

\end{document}