documentclass[varwidth,margin=0.5cm]{standalone}

usepackage[french]{babel} % Comment to avoid error
usepackage[utf8x]{inputenc}
usepackage[T1]{fontenc}
usepackage{csvsimple}

begin{filecontents*}{TestSemicolon.csv}
surname;name
MOUSE;Mickey
DUCK;Donald
end{filecontents*}

begin{document}
  csvreader[
    head to column names,
    separator=semicolon,
    ]{TestSemicolon.csv}{}{%
    surname~name\
    }%
end{document}

Undefined control sequence

documentclass[varwidth,margin=0.5cm]{standalone}

usepackage[french]{babel}
usepackage[utf8x]{inputenc}
usepackage[T1]{fontenc}
usepackage{csvsimple}

begin{filecontents*}{TestComma.csv}
surname,name
MOUSE,Mickey
DUCK,Donald
end{filecontents*}

begin{document}
  csvreader[
    head to column names,
    ]{TestComma.csv}{}{%
    surname~name\
    }%
end{document}