![alt text][1] Ma Il n'y a pas un ECM, mais ma boule de cristal dit que vous avez besoin de `\renewcommand\theHchapter{\thepart.\thechapter}` : \documentclass{book} \usepackage{hyperref} \renewcommand\theHchapter{\thepart.\thechapter} \begin{document} \part{part 1} \chapter{title} \label{foo} \part{part 2} \setcounter{chapter}{0} \chapter{title} \label{test} \ref{test} \end{document} [1]: https://texnique.fr/osqa/upfiles/Screenshot_2021-10-12_at_12.42.42.png

![alt text][1] Ma boule de cristal dit que vous avez besoin de `\renewcommand\theHchapter{\thepart.\thechapter}` : \documentclass{book} \usepackage{hyperref} \renewcommand\theHchapter{\thepart.\thechapter} \begin{document} \part{part 1} \chapter{title} \label{foo} \part{part 2} \setcounter{chapter}{0} \chapter{title} \label{test} \ref{test} \end{document} [1]: https://texnique.fr/osqa/upfiles/Screenshot_2021-10-12_at_12.42.42.png

![alt text][1] \documentclass{book} \usepackage{hyperref} \renewcommand\theHchapter{\thepart.\thechapter} \begin{document} \part{part 1} \chapter{title} \label{foo} \part{part 2} \setcounter{chapter}{0} \chapter{title} \label{test} \ref{test} \end{document}\end{document} [1]: https://texnique.fr/osqa/upfiles/Screenshot_2021-10-12_at_12.42.42.png

\documentclass{book} \usepackage{hyperref} \renewcommand\theHchapter{\thepart.\thechapter} \begin{document} \part{part 1} \chapter{title} \label{foo} \part{part 2} \setcounter{chapter}{0} \chapter{title} \label{test} \ref{test} \end{document}