Pgfplot fill between error

Question

for some reasons, this code doesn't work in my document:

\documentclass{article}
\usepackage{fancyhdr} % Required for custom headers
\usepackage{lastpage} % Required to determine the last page for the footer
\usepackage{extramarks} % Required for headers and footers
\usepackage[usenames,dvipsnames]{color} % Required for custom colors
\usepackage{graphicx} % Required to insert images
\usepackage{courier} % Required for the courier font
\usepackage{tikz}
\usepackage{pgfplots}
\usepackage{lipsum} % Used for inserting dummy 'Lorem ipsum' text into the  
 template
\usepackage[francais]{babel} % For French
\usepackage[latin1]{inputenc} % Standart input, need it for accents
\usepackage{amsmath, amssymb} % Real number R, Complex C etc...
\usepackage{sectsty}  % For title/section color
\usepackage{xcolor} % For title/section color
\usepgfplotslibrary{fillbetween}
\pgfplotsset{compat=1.12}

\begin{document}

\begin{center}
\begin{tikzpicture}
\begin{axis}[axis lines=middle,samples=200]
  \addplot[name path=f, blue] {x/((1+x^2)^2)};
  \addplot[draw=none, name path = xaxis] {0};
  \addplot[blue!30] fill between [of=f and xaxis, soft clip={domain=1:2}];
\end{axis}
\end{tikzpicture}
\end{center}

\end{document}

But if i use delete \usepackage[francais]{babel}, it's working. Howewer, i need this package to write in french.