\pdfcompresslevel=0
\documentclass[a4paper]{article}
\usepackage{german}
\usepackage[utf8]{inputenc}

\usepackage{pgfplots}
\usepackage{pgfplots.assert}

\usetikzlibrary{intersections}
\usetikzlibrary{pgfplots.decorations.softclip}
\usepgflibrary{fillbetween}

\begin{document}
\thispagestyle{empty}
\parindent=0pt
\parskip10pt

\begin{tikzpicture}
	\begin{axis}[smooth]
	\addplot+[name path global=A,samples=5] {x^2};

	\addplot+[name path global=B,domain=-6:7,samples=5] {-2-x^2};

	\fill[yellow]
		\pgfextra
		\expandafter\let\expandafter\A\csname tikz@intersect@path@name@A\endcsname
		\expandafter\let\expandafter\B\csname tikz@intersect@path@name@B\endcsname
		\pgfpathfillbetween{\A}{\B}
		\endpgfextra
	;% 
	\end{axis}
\end{tikzpicture}



\end{document}

