\usepackage[absolute]{textpos}
\newenvironment{DUCLASSheader}
    {   % renew the itemize command in order to apply a flushright to each elements
        \let\olditemize\itemize% 
        \renewcommand\itemize{
            \olditemize%
            \raggedleft%
            \setlength\itemsep{0.0em}%
            \small}%
        \raggedleft%
        \em%
        % A textblock is created for placing the header in the topright corner
        \begin{textblock*}{\linewidth}[0,0](2cm,1.5cm)%

        % Create a new group for the color gray
        \begingroup%
        \color{gray}%
    }
    {   
        \endgroup%
        \end{textblock*}%
    }