Un court code pour un filet mignon avec `eso-pic` et `longfbox`:
\documentclass[french]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{ebgaramond}
\usepackage[svgnames]{xcolor}
\usepackage[paperheight=70cm,paperwidth=54cm,hmargin=2.5cm, includeall, vmargin=2cm,
nomarginpar]{geometry}
\usepackage{blindtext}
\usepackage{babel}
\usepackage{eso-pic}
\usepackage{longfbox}
\AddToShipoutPictureBG{%
\AtTextUpperLeft{\hskip-1.5pt\lfbox[height=\textheight, width=\textwidth, border-color =IndianRed, border-width=1.5pt, padding=0pt]}{}%
}
\begin{document}
\Blinddocument
\end{document}
![alt text][1]
[1]: https://texnique.fr/osqa/upfiles/filetdemarge(s).png
