documentclass[11pt]{book}
usepackage[dutch]{babel}
usepackage{amsmath}
usepackage{xcolor}
usepackage{framed}
usepackage{titletoc}
usepackage{etoolbox}
usepackage{lmodern}
definecolor{myred}{RGB}{127,0,0}
definecolor{myyellow}{RGB}{169,121,69}
patchcmd{tableofcontents}{contentsname}{sffamilycontentsname}{}{}

usepackage{xcolor}
usepackage{framed}

definecolor{myred}{RGB}{127,0,0}
definecolor{myyellow}{RGB}{169,121,69}

renewenvironment{leftbar}{%
  defFrameCommand{{color{myyellow}vrule width 2pt depth 6pt} hspace{10pt}}%
  MakeFramed {advancehsize-width FrameRestore}}%
 {endMakeFramed}

makeatletter
def@chapter[#1]#2{ifnum c@secnumdepth >m@ne
                       if@mainmatter
                         refstepcounter{chapter}%
                         typeout{@chapappspacethechapter.}%
                         addtocontents{toc}%
                                   {%
                                       {protectparbox{3.5em}{hfillHugecolor{myred}bfseriesthepage}}%
                                         protecthspace*{.5em}
                                        protectparbox{dimexprlinewidth-4emrelax}{%
                                           protectbegin{leftbar}
                                              {scshapesmallchaptername~thechapter}\sffamily#1%
                                           protectend{leftbar}}parnoindent
                                    }%
                       else
                         addcontentsline{toc}{chapter}{#1}%
                       fi
                    else
                      addcontentsline{toc}{chapter}{#1}%
                    fi
                    chaptermark{#1}%
                    addtocontents{lof}{protectaddvspace{10p@}}%
                    addtocontents{lot}{protectaddvspace{10p@}}%
                    if@twocolumn
                      @topnewpage[@makechapterhead{#2}]%
                    else
                      @makechapterhead{#2}%
                      @afterheading
                    fi}
makeatother
usepackage{graphicx}
usepackage[margin=2cm, paperwidth=210mm, paperheight=297mm]{geometry}
begin{document}
renewenvironment{leftbar}
  {defFrameCommand{hspace{6em}%
    {color{myyellow}vrule width 2pt depth 6pt}hspace{1em}}%
    MakeFramed{parshape 1 0cm dimexprtextwidth-6emrelaxFrameRestore}vskip2pt%
  }
 {endMakeFramed}

titlecontents{chapter}
  [0em]{vspace*{2baselineskip}}
  {parbox{4.5em}{%
    hfillHugesffamilybfseriescolor{myred}thecontentspage}%
   vspace*{-2.3baselineskip}leftbartextsc{smallchaptername~thecontentslabel}\sffamily}
  {}{endleftbar}
titlecontents{section}
  [8.4em]
  {sffamilycontentslabel{3em}}{}{}
  {hspace{0.5em}nobreakitshapecolor{myred}contentspage}
titlecontents{subsection}
  [8.4em]
  {sffamilycontentslabel{3em}}{}{}
  {hspace{0.5em}nobreakitshapecolor{myred}contentspage}

tableofcontents
newpage
pagenumbering{arabic}
chapter {chapter one}
some text
chapter {chapter two}
end{document}