###Je souhaite bonne chance avec le baccalauréat!
On peut utiliser
\RedeclareSectionCommands[
tocentryformat=\color{Indigo},
tocentrynumberformat=\color{Indigo},
tocpagenumberformat=\color{Indigo}
]{subsection}
----
\documentclass[a4paper, 12 pt, twoside, french]{scrartcl}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[light, largesmallcaps]{kpfonts}
\usepackage[svgnames, dvipsnames]{xcolor}
\usepackage{microtype}
\addtokomafont{section}{\color{Bittersweet}}
\addtokomafont{sectionentry}{\color{Bittersweet}}
\addtokomafont{subsection}{\color{Indigo}}
\RedeclareSectionCommands[
tocentryformat=\color{Indigo},
tocentrynumberformat=\color{Indigo},
tocpagenumberformat=\color{Indigo}
]{subsection}
\usepackage{lipsum}
\usepackage{babel}
\begin{document}
\tableofcontents{}
\section{Première section}
\label{sec:1}
\subsection{première sous-section}
\label{subsec:1}
\lipsum[1]
\subsection{deuxième sous-section}
\label{subsec:2}
\lipsum[2]
\section{Seconde section}
\label{sec:2}
\subsection{troisième sous-section}
\label{subsec:3}
\lipsum[3]
\end{document}
![alt text][1]
[1]: https://texnique.fr/osqa/upfiles/Screen_Shot_2019-02-12_at_22.00.13_lLXAynN.png
