\documentclass[a4paper,12pt,french]{report}
\usepackage{xpatch}
\makeatletter
\patchcmd{\@part}{\addcontentsline{toc}{part}{\thepart\hspace{1em}#1}}{\addcontentsline{toc}{part}{\protect\numberline{\thepart}#1}}{}{}
\makeatother
\usepackage{hyperref}
\begin{document}
\tableofcontents
\part{Première Partie}
\part{Seconde Partie}
\part{Troixième Partie}
\part{Quatrième Partie}
\end{document}
![alt text][1]
[1]: https://texnique.fr/osqa/upfiles/Screenshot_2022-04-18_at_19.49.04.png
