\documentclass[a4paper, 12pt, twoside]{report}
\usepackage[utf8]{inputenc}     % LaTeX, comprend les accents !
\usepackage[T1]{fontenc}
\usepackage[francais]{babel}
\usepackage{lmodern}
\usepackage{ae,aecompl}
\usepackage[top=2.5cm, bottom=2cm,
            left=3cm, right=2.5cm,
            headheight=15pt]{geometry}
\usepackage{graphicx}
\usepackage{eso-pic}    % Nécessaire pour mettre des images en arrière plan
\usepackage{array}
\usepackage{hyperref}
\usepackage{lastpage}
\usepackage{float}
\usepackage{graphicx}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{mathtools, nccmath}

\usepackage{booktabs}

\usepackage{caption}
\usepackage{subcaption}
\usepackage{placeins}
\usepackage{placeins}
\captionsetup{justification=centering, font=small}
\captionsetup{skip=2pt}