\usepackage{float}

\floatplacement{figure}{htbp} % here, top, bottom, extra-page
\floatstyle{plaintop}
\restylefloat{figure}


\usepackage{caption}
\captionsetup[figure]{labelfont=bf,textfont=normalfont,name=Schéma}

\let\legacyFigure\figure
\let\endlegacyFigure\endfigure

\renewenvironment{figure}{%
  \begin{legacyFigure}%
%  %  \begin{mdframed}[linecolor=gray]%
%  \begin{mdframed}[topline=false,%
%    bottomline=false,%
%    rightline=false,%
%    leftline=false,%
%    linecolor=black,%
%    linewidth=3pt,%
%    %skipabove=0.5cm,%
%    ]
}{%
%  \end{mdframed}%
  \end{legacyFigure}%
}