How to force equal spaces around French quotation marks?

Question

this is again a noob question, and I guess a very generic one. In my French text, I use French quotation marks (the opening one is followed by a non-breaking space, the closing one is preceded by one).

My issue is that those non-breaking spaces are used as regular blank spaces, to adjust the width of a line, which results in uneven spaces between the quotation marks (guillemets) and the quoted text, which is really ugly:

Is there a way to force LaTeX to make those 2 non-breaking spaces the same width at least for a single pair of quotation marks?

EDIT:

I have manually inserted non-breaking spaces at relevant places around punctuation marks:

 les deux jeunes «~Picards~» Michel et Guibert

What bothers me is that those spaces are stretched unevenly. I have to use XeLaTeX,

Answer 1

You can tell babel-french to use «» for the guillemets, but there is also a “command form”.

Note that whether you use spaces after « or before » is immaterial; however, remember “backslash-space” after \fg if you want a space when you use the command form.

\documentclass[a4paper]{article}
\usepackage[french]{babel}
\usepackage{fontspec}

\frenchsetup{og=«,fg=»}

\begin{document}

les deux jeunes «Picards» Michel et Guibert

les deux jeunes « Picards » Michel et Guibert

les deux jeunes \og Picards \fg\ Michel et Guibert

\end{document}

Or you can use polyglossia instead of babel, but in this case there is no “command form”.

\documentclass[a4paper]{article}
\usepackage{fontspec}
\usepackage{polyglossia}

\setmainlanguage{french}

\begin{document}

les deux jeunes «Picards» Michel et Guibert

les deux jeunes « Picards » Michel et Guibert

\end{document}

For completeness, here's with pdflatex.

\documentclass[a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage[french]{babel}

% use « and » for guillemets
\frenchsetup{
  og=«,
  fg=»,
}


\begin{document}

les deux jeunes «Picards» Michel et Guibert

les deux jeunes « Picards » Michel et Guibert

les deux jeunes \og Picards \fg\ Michel et Guibert

\end{document}

Answer 2

The csquotes package provides the command \enquote that should be of interest to you.

% !TEX TS-program = xelatex
\documentclass{article}
\usepackage{polyglossia} % load 'fontspec' automatically
\setmainlanguage{french}
\usepackage[french=guillemets]{csquotes}

\begin{document}
les deux jeunes \enquote{Picards} Michel et Guibert
\end{document}