The following MWE results in this output. Spacing, alignment and font sizes can ouf course be altered to suit your needs.
In order to make sure the header is aligned with the left margin, I have added \noindent right before the \includegraphics command. (Here I have replaced your image file with an example image). In order to make sure, the text is right aligned and is placed at the right margin, I have used \hfill between the image and the tabular. In the tabular itself, I have used an r type column (for right alignment) as well as @{} to remove the small horizontal white pace that is added to either side of a text inside of a table cell. In order to bottom align image and text, I have added [b] to the tabular and valign=b to \includegraphics. The latter is only available if you add \usepackage[export]{adjustbox} to your preamble.
To other, unrelated changes: I have replaced francais with french (in the babel option). If you use the frormer, you should recieve a warinign about this option being deprecated. In addition to that, I have removed \usepackage[latin5]{inputenc} in order to use the default utf8 inputenc instead.

\documentclass[10pt,a4paper]{report}
\usepackage[french]{babel}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{graphicx}
\usepackage{lmodern}
\usepackage[export]{adjustbox}
\usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry}
\author{BATON SOFIAN}
\begin{document}
\noindent
\includegraphics[scale=0.5, valign=b]{example-image}
\hfill
\begin{tabular}[b]{@{}r@{}}
Tribunal...\\
\bfseries COMMUNIQUE ...\\
Luxembourg\\[20pt]
Ordonnance... \\
Luká\v{s}...\\
\end{tabular}
\smallskip
\hrule
\end{document}
\documentclass{...}and ending with\end{document}. – TobiBS Aug 15 '20 at 08:26