%!TEX pdflatex

\documentclass[french,a4paper,11pt]{article}
\usepackage[margin=1.5cm]{geometry}
\usepackage{babel}
\usepackage{bm}
\usepackage{tikz}
\usetikzlibrary{calc}

\begin{document}

\part{Test}

\newcommand\blocpave[4][orange]{%1=couleur,2=posCBG,3=hauteur,4=label
	\coordinate (decalshift) at (#2);
	\begin{scope}[shift=(decalshift)]
		\draw[fill=#1!30] (0,0,0) -- ++(1.25,0,0) -- ++(0,#3,0) -- ++(-1.25, 0, 0) -- cycle;
		\draw[fill=#1!60] (0,#3,0) -- ++(1.25,0,0) -- ++(0,0,-1) -- ++(-1.25, 0, 0) -- cycle;
		\draw[fill=#1!90] (1.25,0,0) -- ++(0,0,-1) -- ++(0,#3,0) -- ++(0,0,1) -- cycle;
		\draw ({0.5*1.25},{0.5*#3},0) node[text width=1.25cm,text centered,font=\sffamily\scriptsize] {#4} ;
	\end{scope}
}

\begin{tikzpicture}[line join=bevel]
	%sol
	\draw[fill=lightgray] (-1,0,1) -- (14.25,0,1) -- (14.25,0,-2) -- (-1,0,-2) --cycle;
	%pavés
	\blocpave[orange]{0,0,0}{3}{Prix d'achat brut HT}
	\blocpave[green]{1.5,2.25,0}{0.75}{Remises}
	\blocpave[orange]{3,0,0}{2.25}{Prix d'achat net HT}
	\blocpave[blue]{4.5,2.25,0}{1}{Frais d'achat}
	\blocpave[orange]{6,0,0}{3.25}{Coût d'achat HT}
	\blocpave[blue]{7.5,3.25,0}{1.25}{Marge}
	\blocpave[orange]{9,0,0}{4.5}{Prix de vente HT}
	\blocpave[blue]{10.5,4.5,0}{1.25}{TVA}
	\blocpave[orange]{12,0,0}{5.75}{Prix de vente TTC}
	%légendes
	\draw[thick] ({1.5+0.5*1.25},3,-1) node[draw,circle,above=4pt,red] {$\bm{-}$} ;
	\draw[thick] ({4.5+0.5*1.25},3.25,-1) node[draw,circle,above=4pt,red] {$\bm{+}$} ;
	\draw[thick] ({7.5+0.5*1.25},4.5,-1) node[draw,circle,above=4pt,red] {$\bm{+}$} ;
	\draw[thick] ({10.5+0.5*1.25},5.75,-1) node[draw,circle,above=4pt,red] {$\bm{+}$} ;
	\node[black,font=\sffamily\bfseries] (FOUR) at ({0+0.5*1.25},0,2) {Fournisseur} ;
	\node[black,font=\sffamily\bfseries] (COMMER) at (6,0,2) {Commerçant} ;
	\node[black,font=\sffamily\bfseries] (CONSO) at ({12+0.5*1.25},0,2) {Consommateur};
	\draw[ultra thick,orange,->,>=latex] (FOUR) -- (COMMER) ;
	\draw[ultra thick,orange,->,>=latex] (COMMER) -- (CONSO) ;
\end{tikzpicture}

\end{document}