tikzpicture as section title but text in table of contents

Question

I want to use a little banner as title in \section. It should look like the banner above "vocabulaire" but the text doesn't change its size and I would like to get rid of the section numbering. My second problem is that I want the banner to appear in the body of the document but not in the table of contents. Is it possible to have only the date there?

\documentclass[12pt]{article}

\usepackage[ngerman]{babel}
\usepackage[a4paper, text={16.5cm, 25.2cm}, centering]{geometry}
\usepackage[sfdefault]{ClearSans}
\usepackage[utf8]{inputenc}
\setlength{\parskip}{1.2ex}
\setlength{\parindent}{0em}


\usepackage{tikz}
\usetikzlibrary{shapes.symbols,shadows}

\definecolor{bancolor}{RGB}{62,96,111}


 \DeclareRobustCommand\datebanner[2]{\begin{tikzpicture}
\node[
  signal,
  signal from=north,
  signal pointer angle=150,
  fill=bancolor!75,
  drop shadow={shadow xshift=0pt, color=bancolor},
  rotate=-90,
  text width=2cm,
  text height=1.5cm,
  anchor=north west
  ] (banner) at (0,0) {};
% the text in the banner
\node[
  anchor=south,
  text width=3cm,
  align=center,
  font=\itshape] 
  at ([yshift=1cm]banner.east) {#1 \\ #2};
\end{tikzpicture}}

\begin{document}

\tableofcontents

\section{\datebanner{2. April}{2018}}


\vspace{64pt}

\begin{tikzpicture}
\node[
  signal,
  signal from=north,
  signal pointer angle=150,
  fill=bancolor!75,
  drop shadow={shadow xshift=0pt, color=bancolor},
  rotate=-90,
  text width=2cm,
  text height=1.5cm,
  anchor=north west
  ] (banner) at (0,0) {};
% the text in the banner
\node[
  anchor=south,
  text width=3cm,
  align=center,
  font=\itshape] 
  at ([yshift=1cm]banner.east) {28. April \\ 2018};
\end{tikzpicture}

\subsection{Vocabulaire}

\subsection{film}


\subsection{grammaire}

\subsubsection{Si + ...}

\subsection{orthographie}

\end{document}

So far it looks like this

Answer 1

This uses the titlesec package to format the section title. The font is set to the default in \titleformat (second argument), which is overwritten with font= in the tikzpicture. Otherwise, the title of the table of contents would be in italic too. The fourth argument sets the distance between the label and the title. Since the label, i.e. the section number, is left empty (fourth argument), 0pt puts the banner at the left.

I also took the freedom to improve your banner command a bit. Using minimum width instead of text width ensures, that the banner adapts to the text, if it is wider.

The code:

\documentclass[12pt]{article}

\usepackage[ngerman]{babel}
\usepackage[a4paper, text={16.5cm, 25.2cm}, centering]{geometry}
%\usepackage[sfdefault]{ClearSans}
\usepackage[utf8]{inputenc}
\setlength{\parskip}{1.2ex}
\setlength{\parindent}{0em}

%added
\usepackage{titlesec}
\titleformat{\section}{\Large\bfseries}{}{0pt}{}{}


\usepackage{tikz}
\usetikzlibrary{shapes.symbols,shadows}

\definecolor{bancolor}{RGB}{62,96,111}

% changed, only one argument now
\DeclareRobustCommand\datebanner[1]{\begin{tikzpicture}
\node[
  signal,
  signal to=south,
  signal pointer angle=150,
  fill=bancolor!75,
  drop shadow={shadow xshift=0pt, color=bancolor},
  minimum width=2.5cm,
  minimum height=3cm,
  align=center,
  font=\normalsize\itshape
  ] (banner) at (0,0) {#1};
\end{tikzpicture}}

\begin{document}

\tableofcontents

\section[1. Mai 2018]{\datebanner{1. Mai\\2018}}

\section[2. April 2018]{\datebanner{2. April\\2018}}

\section[27. September 2018]{\datebanner{27. September\\2018}}


\subsection{Vocabulaire}

\subsection{film}


\subsection{grammaire}

\subsubsection{Si + ...}

%\subsection{orthographie}

\end{document}