How to insert space between the number of a caption and double dots that introduce the label?

Question

Even if I specified the French language in the preamble of my document (Tufte-book documentclass), the formatting of the legends of the figures and tables has been kept in English. So I added to the babel-french package in the preamble a command to replace "Table" by "Tableau" (the term Figure is the same in both languages) and precise at the beginning of the figure and it works:

\documentclass[symmetric,justified,marginals=raggedouter]{tufte-book}
\usepackage[french]{babel}
\addto\captionsfrench{\def\tablename{Tableau}}

\begin{document}

\begin{table*}[h]
 \selectlanguage{french}
 \footnotesize
 \begin{tabular}
 \end{tabular}
 \caption{Example to insert space before double dots}
\label{tab:example}
\end{table*}

\end{document}

On the other hand, in French language, there is a space between the number of the caption and the double dots which present the label of the caption, contrary to what is practiced in English language ("Figure 1 :" and not "Figure 1:").

What should I do to insert this space?

Answer 1

This appears to work:

\documentclass[12pt]{scrartcl}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english,french]{babel}
\usepackage[french]{cleveref}
\usepackage{caption}
% Declare a new caption label seperator with a small math space \, in front of ":"
\DeclareCaptionLabelSeparator{frcolon}{ $\,:$ }
% Set the new label seperator to be used by caption
\captionsetup{labelsep=frcolon}

\begin{document}
French \cref{tab-my_label} seems to be different from English tables...
\begin{table}[h]
    \centering
    \begin{tabular}{c|c}
        a & b \\
        c & d
    \end{tabular}
    \caption{Caption}
    \label{tab-my_label}
\end{table}
\end{document}