Accent in equation list

Question

I'm need to make a list of equation in my document. I found and use the modified version of Lev Bishop's code from here. Everything work until there's an accent in the equation label. I got this error message :

! TeX capacity exceeded, sorry [input stack size=5000].

\@latex@warning #1->\GenericWarning {\space \space \space \@spaces \@spaces ...

l.38 \label{eq:équation}

I'm currently using TeXnicCenter on Windows 7 but I tried others and they all gave me the same error... Do you have any solution ?

Example in Latex

\documentclass[pdftex,a4paper,11pt,twoside]{report}
\usepackage[francais]{babel}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}    
\usepackage{xstring}
\usepackage{tocloft}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\let\oldequation = \equation
\let\endoldequation = \endequation
\AtBeginDocument{\let\oldlabel = \label}
\newcommand{\mynewlabel}[1]{
    \fullexpandarg
    \StrBehind{#1}{eq:}[\Str]
    \myequations{\Str}\oldlabel{#1}}
\renewenvironment{equation}{
    \oldequation
    \let\label\mynewlabel
    }{\endoldequation}

\newcommand{\listequationsname}{Liste d'équations}
\newlistof{myequations}{equ}{\listequationsname}
\newcommand{\myequations}[1]{%
    \addcontentsline{equ}{myequations{\hspace{15pt}\protect\numberline{\theequation}#1}}

 \setlength{\cftmyequationsnumwidth}{3em}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}

\listofmyequations

\begin{equation}
    2+2=4
    \label{eq:équation}
\end{equation}

\end{document}

Answer 1

Labels should contain only ASCII characters, otherwise special characters, that are internally represented with control sequences, expand and you find terrible things in referring to such labels; if you change your label to equ:eqauation, getting rid of that é, everything will run smoothly. It is less French, but it works; after all labels should not be read by humans, but only by the typesetting engine.